Smith Lake recreation area is just a mile off Post exiting through the Honeycutt gate. You can enter from Murchison but if you are towing you should use the dirt road entrance from Honeycutt near the Smith Lake riding stables. It is managed by the MWR group. I posted a review at
RV Park Reviews :: Fayetteville, North Carolina ( NC ) - RV Parks and Campground Reviews.
I called the RDU Parking Office and explained my setup with car in tow and that I would need more than one regular space, maybe the equivalent of three. The nice lady said for now the exit fee was $6/day. She gave me directions to Lot 4 from I540 exit 3, and suggested I use Lane 6. She also said that if I parked more than 30 days to call the office so my vehicle wasn't marked as abandon.
I will find out more this coming Friday afternoon when I go home for a week (I also dread the 4 hour flight!).