As someone who has built a skoolie in nz and now doing it with a 33ft midbus here (first was 40ft), a couple of notes I've just learnt.
Thomas buses, especially C2 are glued metal boxes. Eg +10000 lanour hours to remove all panels.
Also particulates filters DPF, DEF, that stuff, I know US is crazy on that but some in CA bypass and go straight through but I'm still on the Find A Diesel Mechanic page while playing with my angle grinder on extra spicy thick steel bolts that are all rusted in. Surface rust - but again, time.
Time, or labour hours, is a huge cost factor. Also, a fresh safety doesn't mean it is 100% up to par, I have a rusted through bolt on a driver's seat anchor point, therefore zero anchorage.
Oh and on labour hours, the stuff still in - flashers, signs, WHEELCHAIR ACCESS RAMPS, vandalocks!!! Any alarm actually! The diesel heater, the stuff people cry about in their sleep when they try to do it after watching Instagram posts.
Ok gotta go write a post asking for tool advice help to unseat the glue currently holding the steel panels on my bus ceiling before I get sidetracked again...