This brings back memories of the first school bus conversion I ever saw covered extensively online, from the genius mind of Jake Van Slatt [1]. He took the reuse of discarded materials as his main inspiration, and really turned out something beautiful. His blog is full of all sorts of kooky inventions and reclaimed item builds.
He posted two great summaries of the bus interior and construction on his newer website: http://steampunkworkshop.com/bus2.shtml http://steampunkworkshop.com/bus1.shtml
[1] http://www.vonslatt.com/