North-south tracks right through the middle of La Plata (below). Also the east-west run that passes through White Plains, that I believe was being or has been turned into a Rails to Trails recreation path.
Try the areas leading to one of the power plants.
Rt.301 and the Potomac, and rt.231 and the Patuxent.
I use GoogleEarth to find an accessable site, like on rt.301 just south of rt.4.