There are many blogs and YouTube videos about how to build your own RV from an old school bus or van. This probably is not a very cost-effective idea.
Recently I noticed that when I go online I'm being bombarded by "sponsored content" (what we used to call advertisements) which disguise themselves as news stories. All the stories are different but have the same theme: "Woman converts Greyhound bus into tiny home!" one reads, while another touts "Man converts U-Haul truck to amazing RV!" Or perhaps, "This guy converted his van into a amazing compact home!" - and so forth and so on. I'm not sure why they're targeting these ads at me, as I am buying a brand spanking new RV and have no desire to convert an old school bus into a motorhome - that likely would cost more than said brand-spanking-new RV.
Converting some sort of existing vehicle into an RV is probably not a very cost-effective idea. And the reason for this is that you can buy a used RV for not an awful lot of money. Why spend days, weeks, or years trying to make an RV out of an old school bus when you can just go out and buy a second-hand motorhome and go camping the next weekend?
And I say this, knowing full well how poorly most commercially available RVs are made. But as bad as the sticks-and-staples crap that they sell at most RV dealers can be, they look pretty darn good in comparison to some sort of home-made crazymobile that you assemble in your backyard.
The problem falls into four categories. First is cost, second is labor involved, third is quality, and fourth is utility.
Cost is probably the biggest factor. Taking aside the value of your free labor in doing this, you'll end up spending more money buying some sort of well-used vehicle and then buying all the necessary component parts, as compared to buying a second-hand RV. Used school buses are not cheap, and neither are used box trucks, vans, or cargo trailers. These types of vehicles might be half the cost of a used motorhome or trailer, but they don't include any sort of interior appointments. And they are pretty clapped out by the time the School District or U-Haul decides to dump them.
RV manufacturers can obtain parts in bulk and thus buy very cheaply. You, on the other hand have to buy your products at retail. (Hint: If you must go this route, find a wrecked RV to pull parts from). And there are an awful lot of parts that go into an RV. It's not just the air conditioner, refrigerator, the toilet, the stove, the furnace, the hot water heater, and so forth, It's all the necessary plumbing and fittings and accessories and fasteners that are needed to put all the stuff together.
I'm sure you've experienced this firsthand. You go to Lowe's or Home Depot to buy some supplies to do something silly like put in a new electrical outlet or maybe replace the faucet in your house. You just needed a few fittings and maybe an outlet box and your chagrined to see at checkout that you've spent $50 or more. The markup on some of these parts and accessories and fasteners is somewhat extraordinary, at least at the retail level.
The RV manufacturers are buying these things by the bucket load and are getting them for pennies apiece. Meanwhile, you're paying dollars. You'll never come out ahead.
Thus, if you add up the cost of the underlying vehicle involved, plus the parts and components needed to make it an RV, the overall cost is going to be more than that you would pay for a secondhand RV, and in some instances, even more than a new one.
Bear in mind that a big part of cost is depreciation. Our towable RVs we purchased for only a few thousand dollars apiece and after many years have you sold them for... a few thousand dollars apiece. We bought the Casita 15 years ago for $8,375 and sold it last week for $7,500. That's not a lot of depreciation.
Granted, you will experience normal depreciation with your tow vehicle, but in most cases you have to own an automobile anyway, especially in America. But all that being said, the depreciation on a car or pickup truck or even a motorhome is nothing compared to depreciation on your home-built camper. You may spend thousands and probably tens of thousands of dollars building your own camper and when it's all said and done it's worth absolutely nothing in resale value because nobody wants someone else's second-hand crazymobile.
The second problem is labor. It's a staggering amount of labor to build an RV, compared even to a house. We put together our own small house when we built Mark's studio and it took four of us about two weeks to frame it up and put on the roof. It took me more than two years to finish the interior including the wiring and plumbing. That being said, building an entirely new structure is actually an awful lot easier than remodeling. In remodeling, you have to cut things to fit, a very time-consuming, laborious, and tedious process.
When you were trying to retrofit a school bus or a box van to include a bathroom and a sink and all of that, you have to cut and fit each piece to fit the space, which becomes tedious and time-consuming. RV manufacturers build on a flat platform and then assemble everything together. And since they're building dozens of the exact same coach, they can do things on the quasi-assembly line basis. And since they have all the tools and parts laid out, it's much faster for them to build and thus much cheaper.
Expect to spend months, if not years, putting together your dream RV from an old school bus or cargo trailer. Of course, for some people that is the entire joy of the process. They're really not interested in camping so much as they are interested in this hobby that occupies their time. And we've seen this in a lot of areas besides RVing. In the home-built aircraft hobby, many people will build one aircraft after another, losing interest in each one, as soon as they have flown them for the first time.
If the building is your thing, then go for it. But it is an awful lot of labor for the end result involved. And bear in mind that once you've built your "skoolie" or tiny house, odds are you won't have it for more than a few years. While it may seem like a lifetime commitment when you are in your 20's, you'll find it quite tiresome before you hit 30. A used conventional RV might be a cheaper and easier choice.
The third aspect is quality, not only in terms of your own mechanical abilities but as well as the quality of the underlying chassis. My hippie brother used to buy old school buses for their hippie puppet theater, and they would paint them wild colors and drive them around at least for a while. Their hippie commune farm was littered with the carcasses of old buses as they tended to die rather soon after being acquired. Not only are used school buses pretty well wrung out, when hippies start driving them, they break down pretty quickly.
But even if you take care of your skoolie, it's probably not going to last very long as it probably has over a hundred thousand or maybe even two hundred thousand miles. It's very expensive to fix a school bus, as they have heavy-duty components and sometimes diesel engines, which often are hard to work on by the average person in their driveway.
Thus, if you're using an old school bus, or an old U-Haul Van, or an old utility company van or an old cargo trailer, you're going to have problems with the underlying chassis before long. Granted, you'll have some quality problems with a used RV - as I noted before the quality of RVs is pretty scandalous as it is. But a used motorhome with 50,000 miles on it is probably going to give you more reliable service that a used school bus with 250,000 miles.
Then there is the issue of your quality of craftsmanship. Now, if you are an expert carpenter and have all the right tools, you could probably put together a very well-made RV. But hopefully you also have plumbing and electrical skills as well. And wiring up and plumbing an RV is more than just twisting together a couple of wires to put some lights up and an electric fan. If you don't do the wiring properly, it'll give you problems down the road and the entire experience will be an exercise in frustration. Ditto for plumbing, which gets complicated, with installing tanks under the chassis and whatnot - which is why a lot of skoolie conversions skip this step or go to a "hippie shitter" (composting toilet) which is just oddball.
Before you engage in such a project, consider critically your own carpentry and other mechanical skills. Merely maintaining an RV can be taxing of your time and labor. Building one can take an astounding amount of time and labor and require another level of skills.
The fourth aspect is utility. Once you've completed this converted school bus or box van or phone company van or cargo trailer, the question is, is it going to be as useful to you as a more conventional RV purchased secondhand?
If you skipped out on installing some features, such as a bathroom because it is too difficult (and it is) you may find your resultant rig less than useful going down the road. The other problem is many campgrounds shy away from letting people stay if they're camped in a converted School Bus, van, box truck, utility trailer, or the like. Many have explicit prohibitions against such homemade rigs. They assume, often rightfully, the people traveling in such rigs are crackpots. Not only that, the sight of such homemade nightmares often scares away the regular paying customers.
Yes, converted buses and whatnot are creepy and weird and no one likes creepy. Even if you forego the de rigeur covering the bus with bible verses (I've seen it done, more than once) or political statements supporting or denouncing Trump, there is something about a converted commercial vehicle that screams "crackpot inside!" or looks like the home of a child molester. You will have to live with this judgement, whether you like it or not, whether it is fair or not.
Another aspect of utility is resale value. If you went out and bought a lightly-used secondhand RV - and they do exist - and decide you don't like RVing, you can easily sell the RV on the open market. Or after a few years you get tired of living in an RV and decide you want to give it up or perhaps you want to trade up to something bigger or different, you'll have no problem selling your RV, provided you didn't sign one of these idiotic 20 year loans.
A used RV made of a school bus or other vehicle is much harder, if not impossible to sell. No one wants to buy your homemade nightmare, particularly after you've already wrung it out. While the depreciation of manufactured RVs can be quite steep, particularly for motorized ones, and the quality issues are rather dramatic, the same can be said, only worse, for a homemade RV. Basically once you're done with your homemade skoolie, you essentially throw it away. It has little or no resale value whatsoever.
Thus, as an economic proposition, building your own RV really isn't worthwhile, not when manufactured RVs could be had so cheaply. I suppose you could really bottom-feed and buy a used Skoolie that someone else has already converted, but I suspect you'd break down on the way home from buying it.
Like anything else, you have to do the math. Unfortunately, we've sort of fallen into this "do it yourself and save!" mentality in this country, where people actually spend more doing things themselves than simply hiring somebody else to do it for them. I think also, this idea of making an RV or "tiny house" from discarded end-of-life vehicles seems to appeal to a certain segment of the hipster population - young men of a certain age who wear ski hats, in the summer. Is that still a thing?
I should pause here and note that if you are one of these 20-something males contemplating converting an old school bus to live in, that you start to reconsider your life choices. Drugs are likely involved - lets be honest here. Living "off the grid" in an old bus isn't going to enhance your life down the road. Your career - the few years you have it - will be affected, mostly because you are spending your prime earning years in an old bus. Attracting a mate will be harder to do because, you know, women are materialistic bitches who only care about money, right? Wrong - they want a future and have a womb, and aren't impressed with the earning power of a guy living in a bus. You can't blame them for that. As a male, you can plant your seed and then wander off (it is a thing - many species do it). Females want something more lasting.
Think about this carefully. Yes, the cost of housing is high. But living in a bus isn't going to be a gateway to success, only the first step in a long downhill trudge. Giving up on life, so early in life, isn't the answer.
Building your own RV falls clearly into this category of do-it-yourself-gone-wrong. Before you decide to convert an old school bus, or remodel a worn-out Greyhound bus into an RV, consider the plethora of second hand RVs out there for sale that are fairly inexpensive. Not only will they be a lot less labor and hassle on your part, the resulting RV will be nicer and have a higher resale value and provide you with greater utility.
RVing can be a fun way to explore the world and a great form of recreation. Living in an RV, however, other than for a limited period of time, is not a very attractive lifestyle, even for retirees. For those in their prime earning years, even less so. But if you want to go RVing, you can buy an RV fairly cheaply - one that has all the bells and whistles and is designed for the task - at a cost far less than trying to make something out of nothing.