There are other residences about a 1/3 of a mile back up the road from them (mainly trailers). These neighbors might be into things they shouldn't be (*cough* Meth *cough*), but whenever I've seen then around and stopped to talk or introduce myself as their neighbor, they've been quite nice. I've been watching to see one of them out so I can stop to shoot the breeze, and then ask, "By the way, what do you know about our neighbor at the end of the road...?" I suspect the people who live closest full-time know a lot more than I do.
Talked to my brother who is an ER Doc, and he said it definitely involves drugs. He sees that kind of behavior out of addicts every day in the ER.