I managed to wash, sand, and prime with BIN the sides and bottom that were in the garage at the time of the fire.
Looks like they'll be sealed well enough for a topcoat and won't smell.
I put insulation board in the bottom, a quickie floor, and got to work on the framing.
This is where it starts to finally look like a camper.
Passenger side ready for door cutout.

Passenger side 3/4 view:

Driver's side 3/4 view:

Front view:
