We have never hung anything on the walls in any of our RVs due to wall construction and materials. Some people have luck with 3M Command strips and hooks for lighter things but, personally, I wouldn't hang anything like a mirror. There are "studs" (frame members in the wall) which are aluminum, but may not be located exactly where you want to hang things. My personal advice would be to stick to lightweight items and use the 3M Command products.
TV mounting areas are backed by plywood, so the appropriate screws (not too long so you don't go through the outside of the wall) will work there.
Forum tip: You can create a signature block with your RV and tow vehicle information (see mine below). That way you won't have to repeat that information whenever you post or ask a question - and others won't have to ask. You can create a signature by going to:
Forum Actions (on menu bar) -> Edit Profile -> Edit Signature (under My Settings on the left)
Rob