Motion detectors inside the RV, often a single sensor can cover an entire RV, these will detect any major motion (NOTE: if you have a big dog, yup, they will detect, cats not so much but some can).
Cellular notification of owner who can then buzz the fuzz as they used to say.
Campgrounds come in many security levels, About 30 miles from is is a campground where we drove through... and decided to park elsewhere as the place did not give me a feeling of safety.
15 miles in a different direction are two where I felt very secure (As I do here). And making friends with your site neighbors can improve security as well.
Get a statue of an attack dog, equip it with motion sensor eyes and a digital growl (CD, MP3) and ... Well,,, Might work.. Oh, and a hidden camera to record whatever it's growling at.