Traveling to Lynchburg, Va from Bowling Green KY

Though I like the 64 route through the mountains vs. the 40 route, you are too far south IMO to benefit from it. 40 has much more serious grades than 64/77, but still nothing to be too worried about. I'd take the Cumberland/Rogers Parkway over to London, then down to Corbin on 75 and off through the Cumberland Gap on the parkway to hit 40. 4 lane all the way I believe. I've driven that area quite a lot as my wife and I have family spread from Versailles to Somerset.