... Well, I checked and he's so light that he barely compresses the 2" foam so I think it's plenty...
The strength of the bed is also relatively decent...
The problem with my original cushion is more the age and material than the thickness, which is why a good camping pad would be better than mine. I'm sure 2" of good
foam would be suitable.
The weak part of this setup appears to me to be the cabinet front which folds down. The doors in the front then get covered by a very thin piece of plywood. A better platform would be needed for a larger occupant.
There is a structure extending to the floor like Herb describes in the rear gaucho version as well, so the bunk is not supported by the fiberglass shell. I think this is an important point: a bunk of any serious capacity needs this kind of support, and while it is already there in th B1700, it could be added to other trailer layouts.