Smokey Mt. Brewery and Mellow Mushroom are about the only places...besides the Walgreens in Gatlinburg that has S.N. Pale ale...thats about it.
You can get 5oz. samples at Smoky Mt. Brewery and pick and choose which ones you want to try. You can also mix and match six packs in 12oz. bottles.
On the 321 there is a beer and tobbacco shop next to the Dollar Store across from the crafts village. I found it the last time I was up there in the begining of June for vacay. Great selection.