Skyline drive is a national park, have to pay to enter. No commercial traffic, no commuters. The single best road surface I've ever ridden on. The climbs are long and steady at 6-7%, the descents are smooth and fast with sweeping turns. I've only ridden in the off season, early weekday mornings - hardly any traffic. It gets very busy with leaf peepers in the fall. Most of the people going up there are sightseers, hikers, campers - no soccer moms or angry commuters. Tons of cyclists... No huge elevation gains, no real steep sections - just nice steady climbs for the average Joe.

I've only ridden the BRP once, from Marion up to Mt Mitchell. Rt 80 to the BRP, then to the Mt Mitchell access road. Again, offseason - weekday Morning. Rt 80 is an awesome road. Great surfaces, switchbacks, some 10%+ sections, great scenery - I was passed 3 times up the ascent to the BRP. The BRP road surface was rougher, but traffic was limited. Steady climbs of 8-9% with some sweeping descents. The Mt Mitchell access road only goes to the peak, so traffic is limited.