there are some great trails in nc and sc.
in sc, there's the foothills trail, foothillstrail.org, which is spectacular. one of my favorite places on earth. the trail goes through several parks, crosses in and out of nc and sc and has ample water, views, campsites, well maintaned and well marked trails, etc... awesome place.
in nc, not far from the foothills trail area is pisgah national forest which is home to the world famous art loeb trail. you can google that and find a bunch of info on the art loeb. nat'l geographic makes a map of the pisgah ranger district, with all of the art loeb and other spur trails noted. great place, really crowded on weekends whereas i've been on the foothills and have probably only seen people in 1 out of every 3 days most times. very good state parks in sc in the general area of the foothills trail. can't go wrong either way but my money would be on the foothills.