I stand corrected. My guestimate was off. I remember our group leaving Front Royal and spending a whole morning at speed on the Skyline, and only making less than a couple hundred kilometres by lunch. Our group wanted to get down to Deals Gap as soon as possible so we got off and slabbed it the rest of the day to Roanoke.
While on the Skyline, we covered so few centimetres on the map during that morning despite our speed (because of all the twisties) it seemed like it would take days to get down to Deals Gap