Ok so after a trip to the local bus yard...
They don't have much.
All the buses they have are lower ceiling (we want a tall body) but otherwise pretty decent shape. I do have to say it's been years since I've been on a school bus and WOW! They are huge! The maintenance manager was very nice, and helpful - he's in charge of at minimum 1100 currently active buses so he definitely had good info. I suspect we'll see him on this board eventually.
Seeing the buses in person definitely helped us get a better grasp on the scope of the project and cement what we want: a tall body pusher. We also got to see a couple of buses that have been in accidents and I am amazed. They had a pusher that had been rear ended, was considered junk and to be parted out for scrap and it was in startlingly good condition. Yes there was damage, but that same accident would have blown a standard RV into smithereens!! We didn't get all the measurements we wanted (realized of course after we got home) so we'll be going back soon to get a few more, but we've now completely revamped our floor plan..again.
I have some questions about Insulation - we want to use spray in foam and do it ourselves. I found a company that uses closed cell insulation that's rated at 6.7 for 1" and equals out to be $1.04 per square foot which includes the hoses, spray tips, etc. Staying warm/cool is a huge priority for us because we fully intend on traveling and boondocking in all extremes of weather. With the spray in foam, it seems worth it to remove the steel walls and current insulation, frame out the walls, spray in, barrier, and panel over. What about the ceiling? With the tall body buses, we can sacrifice a little space to have better insulation, but would we apply the spray foam in the same fashion for the ceiling and floor? We want to use wood panel (similar to Wild Blue's ceiling - love it) on the ceiling and possibly laminate stick tiles on the floor. As far as the floor goes we want to insulate inside the bus as well as below (thanks Lorna!) but I am concerned with the "squish" factor with insulation on the inside floor. Would a wood floor be worth it over laminate?
Heat source would be primarily wood stove, LP back up (we have a Mr. Heater that can warm our entire house), as well as an oil circulated electric space heater we already have.
If the spray in foam works the way we think it should, we'd most likely also use it under the bus and the storage boxes,then coat it with truck bed liner.
We are also thinking about a way to collect a small amount of rain water from a gutter system, and have it filter through a lifestraw system into the clean water tank. Anyone have experience with that?
edit: and yes we will definitely have an inverter system for solar and wind to charge the batteries with a generator back up. We want to avoid cranking up the bus for anything other than driving.