Skyline drive is a National Park. Entry without a pass is $30 for 7 days. A bargain! https://www.nps.gov/shen/planyourvisit/fees.htm
I don't know about national parks pass. I didn't have one. Cost me 20 or 25$ to enter the skyline drive with a vehicle, as I was doing a north to south road trip. That payment also covers the blue ridge parkway.
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