Beware trim slipping even a tiny bit
I pulled the skirting off around the kingpin area on my 3950 to inspect it. To do that, I had to remove the trim that runs horizontally then vertically at the generator compartment. Many of the screws were rusted and/or broken. I know the trim piece had moved 1/32" but I thought the area was still sealed. Uh uh. Put it all back together with bigger screws and lots of caulking.
Be warned. This is exactly the same thing that caused the floor of my bedroom slide to rot - tiny slip of the trim / rails.
BTW, the switches for the front jacks and light were screwed into foam insulation.