but I'll be heading there in a few months and have heard great things about it.
I assume you have done the following, but if not, definitely check them out first:
Some highly underrated or not-as-well-known spots that I love and are nearby:
Boone, NC: college town nestled up into the mountains. You can go kayaking up the Nolichucky, too (really fun - maybe a bit too much for someone those ages, though) and do a lot of great biking in the area. One of the more scenic spots in the U.S. east of the Mississippi.
Williamsburg/James River area, VA: still one of my favorite trips that I took as a kid, but they may be a tad too young to truly enjoy it.
Bald Head Island, NC
Sea Island, GA
Place I've never been but have heard good things about: