Greg, one thing you might do is be on hand for the next project. If your camper was 20' from where he was going then you might really have a problem. Could be he forgets and headed for what he was looking at. If that is the case, some really good drugs could help the "poor fellow" out." There are a lot of people running around with real and significant, but treatable issues.
Second if he doesn't tear your stuff up when you are around then you might want to reconsider having him around or put up a camera.
You know we had a friend of our children coming around and stuff got gone for weeks at a time. I put the rumor out that I had a camera up and stuff just started staying where I put it. Seemed to have more gas in my truck too.