On a couple of trips to the park, I've heard many stations from many parts of VA and MD (west of Chesapeake Bay) and eastern parts of WV. Never did hear 106.5 in Clarksburg, WV or anything in Pittsburgh, though. I've heard Richmond, rural south central VA and even the Hampton Roads area. I also heard some from Baltimore and one from southern PA (WIKZ 95.1).
I stayed south of the intersection of Skyline Drive and US Route 33 on both occasions. This was with the car radio, and on the AT trail, with the Tecsun PL-310 ultralight radio.
Some of the farthest, mostly line-of-sight, WVHL Farmville, VA, WNOB 93.7 Virginia Beach, WBBC 93.5 Blackstone, VA, WKGO 106.1 in Frostburg, MD, WPZZ 104.7 Crewe, VA, WXJK Farmville, VA.