For now, I'd just put up big signs saying road monitored, and just put some black boxes up in some trees with a magnifying glass though a hole incase they do look. If it persists, then go to real camera I guess, or do a camera every so far since a long road is hard to patrol.
Being off the edge of the highway in the city...
found a transient sleeping under a tree during snow one year
a transient encampment along a fence full of beer cans, clothes, pallets, and other trash
Constantly have tresspasssers... put up bright yellow smilie face print outs on areas where trash has been left to indicate that we did notice. Have had to put a smily face on the back of our garage because a ladder was propped up to one of the back windows... and now our property has brigh orange flagging tape draped left and right over paths that have been worn into the woods.... just to let them know someone is watching.
The ditches along the highway are filled with paper trash and there's even an orbital excercise machine of some sort tossed onto the edge of our property slowly rusting away.