Securing you rig from theft (truck and camper)

Well, most of the responses are......whatever.
To the OPs question, answer is the same thing you'd do for your truck if it didn't have a camper. The important part of the equation doesn't change if there's a camper on it.

For the camper?, same, lock the door. You can always add another lock like a padlock with a hasp, but at that point, it's not really deterring someone who really wants into it.