The wall you have pictured is not the original finished wall it is only the skin. There was a molded plastic shell which attached to the wall and held the electrical switches and an 110 outlet in the front. Depending on the motor home's options there also might have been controls for the TV antenna, sound system or other things AS decided to place there. On my 280 I removed this plastic shell and replaced it with oak paneling, at the same time I drilled, peeled back and exposed wiring that needed to be replaced and updated within the wall. Underneath my wall looks like yours but no one is going to see it unless they remove the oak paneling, plus all the wiring is now up to date and safe.
As for your bathroom you may not like my answer but here's what you do. Remove the mattress on the bed behind the shower area and cut out a hole in the wall to loosen that screw. You will also need to cut another hole in the wall to access your shower plumbing. Do this before you try and rip out the shower. The holes can be covered, mine are with a cover plate in case I ever need to get in there again, then the mattress covers the cover plate. For paint in the bathroom I used a good quality acrylic/latex and it has held up for many years. I scratched it removing the closet to replace some old plumbing and simply touched it up with no noticeable signs.
This is not a complicated undertaking but make sure you are getting advice from those who actually own the model you have.
1994 30' Excella 1000, Chummy III- Ford Excursion- 7.3 Turbo-diesel