We're from NC and, although most of the list is west of the MS River, have visited a few of them.
Cedar Breaks - Never camped there but have hiked a few trails. I like seeing snow in late May. The hoodoos there are almost as nice as those in Bryce but so much less crowded.
Guadalupe Mountain - We like the Dog Canyon CG but would pass on the Pine Springs facility. I think the remoteness is the appeal and the resident ranger before his retirement, was a special guy. We were there a few years back during the Turkey Vulture migration. Watching several hundred buzzards trying to find a roosting spot on a small stand of alligator junipers is hilarious.
Saguaro - I'm a NC farm boy that loves cactii -'nough said.
Big Bend isn't on the list but, other than Christmas and Spring Break we've found it to be uncrowded.
To add an eastern Park to the list, I'll nominate Cape Lookout National Seashore. CALO is the next string of barrier islands in NC south of the more famous Cape Hatteras NS but it's accessible only by boat. A couple of private ferries services will take your vehicle (4WD required) over and camping is allowed most anywhere between the dunes and the high tide line. Tent camping is the most common but I've seen popups and smaller campers along the beach. The Park Service also provides twenty or so rustic cabins on each of the two northern sections (Portsmouth and South Core). These have bunks, ceiling fans, flush johns & showers, kitchens and electricity. No roads or services of any kind, so bring whatever you'll need.
Park Service Cabins
