My neighbor thinks my RV is his to roam about inside of at his will

[Platapus]

The reason I ask is that if the RV has a lock and your neighbor is still entering without your permission, then it goes past what is trespassing (which may be a misdemeanor in your state) to Burglery via Breaking and Entering (which is most definitely a felony in any state). The exact wording may differ from state to state, but the felony aspect is the same.

Trespassing - small
Burglary with B/E - big

Why is this important? Well check with a local legal expert of course, but in many states, if there is a reasonable chance that someone is repeatedly committing a felony on your property, the police are supposed to take active efforts to prevent/catch the perp. This duty to act may not be present when the crime is a misdemeanor (trespassing).

In other words, if you suspect someone is trespassing on your property, the police are not going to stake-out your property to catch the perp. However, for a felony, they should.

Depending on your particular state/county, they may lend you the surveillance equipment. Talk to your local DA too. They may be able to help you in this, or advise you to who you can contact.

The key is to make it clear that you are talking about a felony act.

Good luck with it and again, find a local legal expert who can advise you on the proper words for where you live.