I'm Corky and I have a 1982 Eldorado TransVan, a 24 ft. motorhome version of your trailers, fiberglass one piece honey-comb shell, with no internal framing. I've found much useful information here and hope you folks don't mind a motorhomer joining the group.
I've gutted the house and am now rebuilding the inside after replacing much of the floor and undersupports due to dryrot. I find the lack of having to fight placement of things due to frame constraints WONDERFUL!
Current tasks are remounting and building a cabinet around the one unmovable piece in the rig, the reefer, unmovable because of the roof vent hole. Next is installing the Mustee model 68, 32x32 inch shower enclosure and the Camp Chef on-demand water heater, after food a hot shower is next. Mustee makes a great line of small, CHEAP shower enclosures, like $149 for everything on the 32x32 with free shipping to a local store.
I try to share what I find fighting this rig, just think of it a a Burro
with dualies and a 460 glued on.