Purchase a trail camera stick it in your window the motion sensor will go off about 15' before he gets to the camper. They come with night vision I use them all the time on my property and I take one with me when we go camping . I have a 8 gig SD card so you can pictures / movies for a long time. You also have a time date stamped on each picture. When you get his picture show his parents and if they don't care show the cops. Just out smart the little sh-t .
Last resort squirt gun full of your peep it worked on my neighbors dog they don't come over anymore.