Find a Park in map of Pennsylvania
Ridley Creek (30 mins away)
Lake Nockamixon (1,5 h away, toward Lehigh valley)
skiing (poconos)
whitewater rafting in Lehigh Gorge State Park
New Jersey shore: official site & guide with list of beaches including sea isle beach and wilwood beach & here (I know nothing about it other than being the closest to home)