If you haven't already found this website, it's got a very detailed description and at least 1 video of every major rapid on the upper and lower Gauley. The guy's high pitched twangy voice gets old real fast but he does tell you the best lines to take. And I will say this - after watching all the videos, the guy had me scared shitless about undercuts and sieves. He's right on about them being there, but he makes it out to be like every one of them will swallow you whole. I swam 3 of the Class 5 at least once, and I'm still here. Almost all the undercuts are easily avoidable (but I guess it's not a bad thing to know where to avoid if you take a swim).
Rapids of the Gauley River Video Tour
Note - even though I was going for Fall high flow, I still watched the low water videos he put on there to help understand what makes the Gauley so gnarly.
Other tips: Last year the actual festival part of Gauley Fest was in Summersville north of the Walmart by/behind the baseball & football fields. We camped just outside the pay area and weren't hassled(but we were also there Thursday night). The fest costs I think 20 bucks, but I would say it was worth the free schwag, music, raft/kayak porn, and killer deals. Bring cash for the killer deals.... not many took CC's. Expect all your stuff to be wet with monster humidity each morning which also translates into a pretty chilly morning until the sun's out. The water seems like bathwater compared to snowmelt, but it gets a little chillier the longer or more times you're in it. Don't spend too long at Pillow because you end up missing all the action at Sweet's.
Pies & Pints was good, but there's nothing that says WV like Tudor's Biscuit World in Fayateville!
If you have more questions PM me. I'm catching a float with some Ark guides out there over the same time you're there.