You shouldn't have any problems from Charleston south. Speed limit is 70 and traffic moves right along.  I 74 south to 40 is all good road. If you have a few minutes stop at pilot mountain. You go right by .   For a northerner,dropping over fancy gap in Virginia is a real sight on a clear day. Foggy morning ,not so good.  We go to the Winston Salem area so been there many times.  Make sure when you get Winston-Salem you don't take Business 40. It is about a mile before the new I40 exit.it goes to your right.  I 74 is all good driving.