You'll sometimes see higher prices on the main drag a tourist would take into a tourist spot because tourists are not as price sensitive, but this appears to be a decent size town with 15 or 20 gas stations spread throughout, sometimes with 2 or 3 stations to a corner. There should be more than enough competition for the local trade.
There are a lot of tourists in Somerset. And it's not big enough for there to be many gas stations that aren't on the main drag.
(Ever been to Pigeon Forge?)
ETA - If it is in fact due to the tourist trade, an examination of seasonal price changes should make that fairly clear. The Buckeye Navy packs up and goes home in the fall...