Hey, We started from Asheville, NC towards Roanoke, VA (which would have been 8-9 hrs nonstop, but got off it after 5 hours). Given the speed limit and possible slower vehicles and the areas of poor visibility, it is a VERY long drive if you want to stay on it the entire way. A straight shot, nearly nonstop, would be probably something like 12 hrs. I imagine you will have some attractions in mind to see that will add to this estimate, depending on the length of your stops. However in all honesty, you may want to do just a portion of the parkway, as it looks all the same after a while, and then get back on the highway (through many connections). Pick a segment where you see your potentially interesting attractions and enjoy that segment. Otherwise plan to have an overnight stay somewhere on the parkway. Hope this helps!