There's a nice trail around Hagen-Stone State Park south of Greensboro. It's pretty level, with just a couple of mild climbs and descents. I put on my backpack (loaded with about 30 pounds) and took off on the longest trail available (only about 4 miles). An hour and a half later, I had worked up a good sweat and got my breathing up. I had a little discomfort in my feet (both of them actually) but nothing major. So far, so good. When I got back to the truck I immediately took off the shoes and socks and stretched/massaged both feet.
Now an hour later the left heel is a little tender and the right foot is sore where the old neuroma is acting up. I am going to soak them both in ice water first, then massage them again. But, at this point, I don't feel anything that would keep me from returning to the AT.
Tomorrow I will drive to Stone Mountain State Park where there are some steep climbs and descents on the trail to the back country campsites - that will be a good test for sure.