Ok, I see you're focused on the Fords, even though both the older 5.4 and V-10 can blow out or break off their spark plugs and lose header bolts, all at really high repair expenses (especially with Van bodies), and then there's also the lovely 6.0 diesel with all of its problems....
So how about this one (not mine):
04 SMB with 4X4 Quigley Convo, pop top, seats five, sleeps four, is within your budget ($37,500), has 6.0 V8 gasser, sink, microwave, Refrigerator, Stowaway porta potty,Power inverter power and water hook ups and Aluminess rear bumper with Spare tire and extra storage compartment attached.
https://losangeles.craigslist.org/sfv/r ... 43226.html
I have a truck and a B+ with the Chevy 6.0 and can swear by them (not at them).