I too have only done chunks of it. The bottom end of Skyline drive is 2.5-3 hours away, so club members get together to go climb there every couple months (when it's warm enough!).

Don't miss Roanoke-it's about a 30 minute ride off the parkway, it's an oasis of culture in the middle of backwoods VA. The downtown has great shops and restaurants, very neat "feel" to the town, and even though the roads are busy, the cars seemed more considerate than what I'm used to.