"we thought travel to an area of interest and stop at a camp ground, unhook the trailer and then use our truck to tour the surrounding area."
Exactly what I do. No problems for me or anyone I know. I lock the coupler, place a lock that fits into the hitch receiver AND lock my chains with a padlock. At least it will slow them down.
On the other side, this is what I like to do and am insured. So the chance of theft is one I've decided to risk. If my TT is stolen I'll take the insurance money and some savings and buy another Winnebago.