One of the spots I used to go was called SPOC. The Stansbury Park Observatory Complex. It's a condo complex with an observatory at one end. The police there will turn OFF their lights when they see you have a scope set up in the parking lot.
Usually.
I did learn that the truck gate to Hill AFB is not actually on the border of the base, but about 300 yards inside the perimeter. There are no signs or anything, and it's freely accessible by the public, until you start to set up a camera with a 500mm lens to get some shots of Comet McNaught. Then you have to explain to the nice air police sergeant that there really is a comet out there in the sunset and that it is, despite the look on his face, cool to be able to see naked eye, while the sunset is in progress. From the sounds of the radio conversation, the dispatcher didn't really buy the story either.