There is a range on I-80 around Clearfield, PA. I can't remember the name, but I think it's at least 600 yds. Also, do a search for a "Palmasino" (spelling?) range in Wapwallopen or Nescopeck PA. I believe this range was owned or started by one of the creators of the PPC. I could be way wrong on that!
there is a 300yrd range on the state game lands on rt93 broad mountain. unless you want to go to eastgreenville and pay by the hour for a 600yrd range.