Full Timer Questons

I put a cheap little safe in my motorhome, a Harbor Freight special. It's not fire resistant (and so comparatively lightweight), nor is it really that secure, but it should keep the kids out of the s'mores chocolate and so forth. So yes, I do think it is practical to install a safe if you think it needful/useful, depending on the size and weight.

Security, of course, depends as much on how the safe is attached to the RV as how secure the safe itself is. I also agree that keeping it out of sight of casual observers is a wise idea.