Top on our list:
Assateague National Seashore: best October through April, also state park located there, close to Ocean City, beautiful deserted beaches. When we lived here, went 6-8 times a year.
Shenandoah National Park: best in October and April but good May-September, many caves and small Appalachian towns, excellent hiking. When we lived here, went 4-6 times a year.
Hunting Island State Park (Beaufort, SC): get a beach side site. Best October through April, good other months (rumored to be buggy in the back area during the summer). Absolutely beautiful beach located near lovely town of Beaufort, SC. Stay every time we pass through SC, about 2 times per year.
