Somebody mentioned going through HKY enroute to Boone. While US 321 is the most direct route, you may want to check on the status of construction that has been underway on US 321 near Blowing Rock. If this construction is still ongoing (as this link seems to indicate) I would HIGHLY recommend that you take I-77 north to US 421 North. This route is freeway/4 lane highway and will save you a lot of headaches.

Just a thought.

Jammer