I've read all through this discussion can see a lot of work, money, and time in such a project.
As an alternate to undertaking on this Bus, would it be worth your time to do some searching
for School Systems who are wanting to dispose of older units by the end of this school year. They may
be more expensive but usable as is. Simply removing the interior, and building. Then painting the exterior
white.
The advantage ? You can still live in it while fixing the interior and save just the same. Paying off the cost
while working a second job may be more practical for you.
You would need to find some Bus drivers and ask them for some time to talk to you about their Bus over a cup of coffee. Then try to learn about the mechanics who maintain them and get introduced to them. This could get you some inside track info through that network. You may be able to learn which of the Bus "makes" are the best and the ones to avoid.
Back in 2003 a fraternal lodge I belong to purchased a Bus like this one for $1500. It had the wheel chair access too.
One of the members was telling me that out where he lived there was one sitting for sale for $750.
(just like it) We agreed not to say anything as it would just make bad blood within the lodge.
But the one for $750 had been driven on a 120 mile a day route on 4 lane highway throughout it's
service life. (used to take special needs kids to school) It was in need of a new alternator which would have cost less than $75 dollars and an hour to replace. I thought seriously about buying it and then found the
high top E350 I now own.
The point is that I've owned a few "do it yourself kits" in the past and have learned the lessons of pushing boulders up hill.
See if you can meet some Bus drivers and find out what you can from them about upcoming auctions, sales,
and what they can tell you in general. It may make your quest more successful and put you on the road sooner with far less hassle. Then you could focus on what you would be best suited to do, fixing up the interior the way you want it. And you would probably have the same amount of money in it without the blood, sweat, and tears of fixing it up, from the ground up, to be road worthy.
Remember this is just my opinion based on my experience.