Town parks are under different jurisdiction than county or state. Keep checking and asking.

Abandoned factory parling lots (lamp poles, ugh)

School yards - not while school is in session.

Damns, levees, floodwalls, impoundment dykes, etc.

Farms. ASK FIRST! Cattle are notorious metal eaters and a farmer who just paid a vet to treat his cows for "metal sickness" is apt to shoot you down - and not by operating on the same frequency. You also don't want to be slicing through his alfalfa and throwing castor oil on his red clover feed plot.

Abandoned stretches of roadway. These are gold. I used to go to a stretch of road that was "stranded" by a highway to fly my control line planes. Your personal paved runway until the weeds start to take over. There was one nearby but it has been taken over by R/C cars and it's easier to go to my club's field now.

Which is, of course, the best solution of all. Join an R/C club.