Goodness! That's what I was afraid I'd find when I started the
skirt replacement on mine. Fortunately, the rot didn't extend up into the walls. Rebuilding a camper like this without totally destroying it is almost an art. You have to constantly evaluate how far you're going to take your repairs, and the implications of removing that "next piece".
Before closing the walls back up, I'd recommend replacing all of the fiberglass insulation with pink or blue foam board. It doesn't absorb water like the fiberglass, and probably has a better R value. It's easy to cut with a box cutter, or you can cut it on a table-saw like I did and get them perfectly sized to the voids they fit in.
If you have a swimming pool you might try putting the skin panel in it to help remove the lauan backing. Otherwise, keeping it wet somehow is going to be your best bet.
On my repair, I've found that the two most useful tools have been my
Rockwell Sonicrafter and my
Porter-Cable heatgun. A heatgun may also help getting the plywood backing off the filon.
Good luck with the rest of the repair.
:):)
