I know you already have your plane tickets, but in the future I would recommend any w/e except Gauley fest. The other weekends have many many less people. Later in the season, as the weather gets a little colder, there's a lot less rafts also. Gauley fest is fun, but I would rather have a less crowded river.
Also in if you go during the first 2 weeks of October you can do the Russell Fork, which isn't too far (maybe 2 hours). The Russell Fork usually runs the first 3 weekends in October, Sat/Sun, so it is possible to do friday/monday runs on the gauley and sat/sun runs on the RF. I would recommend a guide for the RF also.
I might try and go out this October. The Russell Fork Rendezvous is the best river festival I have been too. Although it seems to have been toned down a little recently.