All I have to say about the campsite is you want it in a place that you'll pass daily.
I made the mistake of putting mine in a "vacation-y" area, kind of at the undeveloped lower half of my map, and I always forget to go down there and check to see if anyone's there. I'm sure I've missed a couple good villagers that way.
The police station, however, is one of those things where you'll remember to check up on it once in a while naturally, so the location is mostly for aesthetics. That being said, I'd say somewhere in the upper-left where there's not too much development going on. :>