There are no studs or framework of any kind, just the fibreglass which seems to vary from 1/8 to 1/4 inches thick. The dinette table we installed is not attached to the wall. It is a removable leg. The dinette converts to a single bed. We have a grandaughter that comes with us most of the time.
The shelf above the table is attached to the glassed in ledge that the top bunk was hinged to. Anything that you attach to outside walls pretty well has to go right through the walls with the potential for leaks
. Here's a couple of pics of mods.