If your in W PA, you should look into "Hickory Creek" in the Allegany Nat. forest.
Really nice 11 mile loop off "Hearts Content" or just drop into something like 5600 acre wilderness area off FS119 to Middle Hickory creek. Just an outstanding valley!
Camp on the north side of the loop trail and see some monster rock deposits and exposures from out last ice age.
I know the Allegany Nat. forest was free for wilderness camping at Hickory Creek area. It can be foot traffic only, mt. bikes of horses or 4 wheelers. It varies with the area.