Still working on this.....slowly.
I've got the new skirt panels mounted, and I'm about ready to put the filon skin back on. Getting them sized and adjusted so they fit properly has taken quite a few hours. It's taken a little trimming here, and a little building up there. I've been trying to coat all the raw wood with spar urethane as I go along, so I have to stop and let it dry once in a while.
This is the passenger side panel. The blue is Styrofoam insulation cut to fill the voids in the panels. The old panels had fiberglass. The white spots are some epoxy filler used to fill in a few low areas in the original wood.

And this is the driver side, with the bundle of electrical wires tucked back into place.

I had to get creative to drive some screws up through the skirt panels into the wall structure above it. When the camper was built, screws were driven down from the wall into the skirt before the filon was put on. I had to cut those screws to remove the old panel.

One area I had some trouble with was this area where the skirt panels drop down next to the bumper. The panel didn't seem to match the dimensions of the wood used to build the rear wall structure, so the surface that should match up with the back wall was off by 3/8" or so. As you can see, I had to make a tapered shim to fill that area in...........

And allow this skinny strip of filon to match the surface of the back wall, and meet the side of the bumper in the right place. The corner trim will cover almost the entire width of the filon next to the bumper, but it will be a smooth transition now.

On this side, in addition to also needing a tapered shim next to the bumper, it needed another one on the side of the back wall to make the two surfaces even. There are probably easier ways to do this, but I enjoy playing with my tools.
Both shims have been glued and clamped in place here.

Having the camper tucked in the corner of the garage gave me two walls to brace against.

I'll get started putting the skin back on soon. I need to figure out how to cut the compartment openings in the filon panels after they're attached. Seems like I've seen a bit for a router or a Roto-Zip for that purpose.
:):)