If you're willing to drive a little further...
Aonia Pass MX track near Augusta, GA has RV hookups (water and electricity) and is open every day. 30 miles northeast of Augusta is Turkey Creek MX, also open every day, but no RV hookups. Another 2 hours east is TNT Motorsports, also open every day, no RV hookups, but staying overnight is also welcome. All 3 of those are mostly clay. About 2 1/2 hours east/southeast of Augusta is Manchester state forest, which has a sand MX track that is also open every day.
If you're interested, let me know and I can post better directions, phone numbers, and closest truck stops with dump stations, restaurants, etc.