This is awesome! I too have purchased a bus for use at college, and operate under the impression that I can completely convert it super cheap and super fast and super nice. I'm finding that it's taking me a quite awhile since I'm not sure what I want to do to the interior yet.
For a roof raise, it would've been best to of done it already. Having 6'4" isn't bad at all though. Mine only has 6' of headroom, and since I'm 6' and plan to put in the same floor that "Experience" has, I'm forced to raise it. For your floor, especially with an old bus, you really should rip it out and replace it. Personally, I thought that Experience's method of insulating would cut down the road noise as well as control the tempature. It's also good to rip out the old floor to repair rust damage. I've heard of people falling through the floor of their bus before, it's best to keep them from rusting through.
I wanted to comment on your insurance. Do some research and see what RVer's who have gotten in accidents are saying about the provider you're looking at.
For the battery. I had a problem with mine when I first got my bus as well, except mine was fine until I got it home. Luckily there was a school bus mechanic at my church the exact moment I needed him. He showed me that you have to fill the battery with water (stating that you can never put too much water in it), which was something I had never heard of doing before. He also told me that a battery would only last 2-3 years, which I was sad to hear. I like the idea of that trickle charger meantioned a few posts back... anyways, I eventually discovered my problem was that the security sensor on the back door was acting up, thus preventing the bus from working. So yeah, I would look to see if your battery is maintained (if it's swelling, then very careffully get rid of it) and filled with water, and try to find out how old it is.
Something nobody has ever suggested (to my knowledge) is that when you do get the answer you want from the DMV, or police, get it in writing, complete with that persons contact information and signature. Do it in a friendly way, "just so we're clear on what the requirements are, would you mind writing them down for me? And can you put your name and contact information there so I can get ahold of you if I run into any complications?"
I'm not sure what you're doing trying to put a bathtub on your bus
. Good Lord. If you plan to have a hose hooked up then I could understand, but do you know how much water you need to fill a tub? You're talking about some really huge water tanks if you start getting into that business.
Just something to point out, there are three kinds of costs with buses that I've noticed thus far. There are those major items (like ovens and refrigerators) that cost a lot, there are unexpected costs (you should always have money set aside for a tow, or if something breaks, such as a caliper or a battery or a tire or something) which throws a monkeywrench into the works, and then there are all the little costs. You go purchase some nails, then some bolts, then some thread sealant tape, some bubblegum, a case of soda, some paint, various little tools, various little items, etc. I believe the term used on this site is "nickle and dime's me to death." Just be very careful about all those little costs, they add up fast. You'd be surprised.
It's really hard to build a bus fast, because it takes a while for people to respond to your questions. I'd also like to know if anyone has put household appliances on the rigs and how that's worked out. I read that full size stoves work great, but refrigerators don't. It was somthing about them needing to be completely level or they'ed turn into heat boxes. I'm curious to hear what anyone might have to say on the subject.
Good luck. I'm planning on putting a ceramic shop on my bus, and I'm gonna get it done by the end of the month! I still haven't gotten all the seats out, so I'll race you!