westend, afraid I haven't been very diligent about taking pics, but here are a few:
Teardown:

Both outer wall studs and taillight brackets rotted

Studs except for corners were less affected, paneling delaminating

Worst damage was across the bottom. Floor sill and rear wall bottom sill completely rotted. Some rot of the floor. This is a shot of the LH rear corner, the longitudinal sill was rotted for about a foot forward. RH rear was sound.
I repaired the floor and sill as best I could, removed the loose material, painted with thin epoxy and patched with epoxy putty where needed. New floor sill, new bottom wall sill, spliced in new studs.

Studs are notched into the bottom sill and scarf jointed at top. Bonded w/ epoxy, with splice plate.

Painted the wall panel with the epoxy and built up with Bondo, the
other handyman's secret weapon :) I had to trim the wall panels flush to the bottom of the floor to replace the floor sill, the blocking is to capture the backside of the panels.

New taillight bracket. Splice for RT rear is just above.
I have done all the work from the outside, as this FW is a rear bath model. Left to right across the back is the wardrobe, toilet, vanity and tub/shower. Too much to remove, and as it turned out most of the damage would not have been accessible from the inside anyway.
This work is being done outdoors, camper is covered with a 29 ft x 49 ft silver tarp from HF. Didn't start until mid December, weather has not been too bad, but I have lost some days. Even on days I can work, they are kind of short, what with the temps and daylight.
I am ready to re-skin it, but I am wondering about installing the other parts afterward. Not sure if the putty tape will conform and seal well in mid 40's temps. Wait for warmer weather?