Fastening backup camera to motorhome

Expect to find a fiberglass layer over a thin layer of ply (luan) and then foam. You can combine screws with double back tape if you want a bit more support. Don't forget to seal the screw holes. I think you may be over-thinking things. It's not rocket science. The manufacturers just drill away and add screws.

There are high tech double back tapes available that would allow you to dispense with screws completely. Folks mount their solar systems to the roof with such tape. I think 3M makes one of them (figures).