I'm always amazed (and pleased) at how many teenagers there are at our local state park riding bicycles, playing bean bag toss, just walking around talking to other kids, swimming and yes spending time with mom & dad.
Huntington Beach State Park near Pawleys Island is a great state park with a great beach, nature trails, marsh walk, nature exhibits and learning center, close to great restaurants, and not far from places spend money. Brookgreen Gardens is just across the street and offers opportunities to learn some stuff.
MB State Perk is also a nice place, a bit closer to the "spend your money here" places.
