US-421 to I-77 - Boone NC
You've been enjoying the Blue Ridge Parkway, seen Linville Falls (and, maybe, the Linville Caverns) and would like to slip over to I-77. Continue north on the Parkway to milepoint 276.4, the crossover of US-421. Turn right onto 421 and enjoy the scenery. Continue past Wilkesboro to Marler and I-77, exit 73 (about 43 miles).
On your right, about 7 miles west of Wilkesnoro, is the entrance to one of the campgrounds of the W. Kerr Scott Reservoir. The other two campgrounds (on the other side of the lake) are accessed from NC-268 which intersects with US-421 just outside of Wilkesboro.