Stealthbiker must be a neighbor. Yeah, I ride Skyline/BRP all the time. Traffic south of Skyland usually isn't a problem except, like, leaf-watcher week-ends. North of there it seems like there's more traffic, and of the hurry-to-get-somewhere variety (I suspect DC area escapees).

If you ride it much, you can buy 1 year pass for $20 (unless it's gone up since last July or August.) If you don't want to pay, you could park near Skyline and carry your bike to the road someplace not visible from an entry station. Personally, I think the fee is money well spent. If you ride from Rockfish Gap, where I-64 crosses the BRP (technically, near Afton, which is down the mountain a mile or so from Rockfish Gap), you can head south which is the BRP, and there's no fee. You'll be doing a lot of climbing for 10 or so miles, but the views on the climb south of the Humpback Rocks Visitor Center are awesome.

I mostly ride from Swift Run Gap, where 33 crosses Skyline. If you head south from there, there's a relatively moderate mix of climbs and descents, and less traffic than north of Swift Run. There's a gas station, store, and restaurant after about 14 miles. After that, there's nothing until Rockfish Gap, another 24 miles. Heading north has you mostly climbing for 4 or 5 miles. There're stores and services at Big Meadows, about 14 or so miles, at Skyland (highest point on Skyline)another ~8 miles, and at Panorama, where 211 crosses Skyline, another ~9 miles. It's pretty much all climbing from Panorama to Skyland.

For the most part, I find the drivers on Skyline and the BRP pretty easy to get along with. They might be preoccupied with sight-seeing, but they aren't usually in a big hurry.

The park service warnings about riding on the parkway are nonsense... it's way better than lots of country roads. Maybe it's oriented towards riders with little experience riding on public roads??? If a ranger catches you riding side-by-side with someone, s/he'll tell you to ride single file. No biggie.