I'm sure you could do it in one day. We didn't want to, so my daughter and I did a loop. Which had a bunch of dirt road hiking back to our car. Depending on how much rain they have some areas are knee deep in mud. It's a fun hike that meanders along the Neuse River back to the Pine cliffs Recreation area. The section we did was from the Ferry Road parking area off HWY 306 between Havelock and Beaufort. Then we hiked to the Pine Cliffs and back up to our car on the HWY. We stayed at the Copperhead Shelter. It is really nice and lots of area to set up a tent around there. I would definitely plan on going before the heat of the summer. It can be miserable there in the middle of July. Really from December through May is pretty good.
Have you spent any time in Uwharrie? Not a lot of hills but some walking time with overnights
+1 for Hanging Rock SP
About an hour further North on the Blue Ridge Parkway is the Rock Castle Gorge. Part of the trail is the original AT with the a shelter Earl Shaffer stayed in. 10.5 mile loop that will kick your butt.
I too have been using Uwharrie and the Birkhead wilderness to get ready for my Springer to Dicks Creek Gap section hike this May. I live out on the coast in Wilmington so the 3 hour drive is the closest trail system with any real elevation change. It's been a great proving ground for me to test out new gear. The Uwharrie and Dutchmans creek trail figure 8 comes in around 18-20 miles IIRC. I'm actually going out there on monday for a 1-2 nighter to test a new tent and push the limit of my winter bag with temps in the mid 20's expected.