Our ameriigo had a mirror on the outside of the closet/bathroom door. We removed the door and took the mirror off (attached with double-sided sticky tape). We're planning to drill four small holes in the frame and put it up with screws in the porta-potty room since amerigos have plywood wallboards, so they're not like the ones with a nice fiberglass inner shell.
Good thing someone mentioned the lighting
; we'll place it where the light
is best instead of disregarding that important point.
Of course, Gilda makes a good point--hey, we're camping! I also just brush quick, put it in a bun, and go. Nice to have a look-see, though, once in a while.