You will be going through Fancy Gap if you go that route. Make sure you time it so as to not hit fog. There have been some significant accidents in that area due to the fog, but if you time it correctly, you won't have an issue. Going southbound, there are run-away ramps for the trucks to use if they lose their brakes. Going north, if you stay out of the right lane, you won't be looking over the side. Very slow trucks stay in the right lane so you should be OK in the middle.
We have driven through there numerous times. We did hit the fog on one southbound trip in the morning. The time we went through the fog, it was not as severe as the times when there were pile ups.
Just be careful and drive through that area when you are not tired.
these links will give you information about I-77 and Fancy Gap
http://www.roadstothefuture.com/I77_VA_Fancy_Gap_Photos_Fullpage.htmlhttps://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=i-77+fancy+gap+va
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