Not knowing the terrain, I'd say you have two choices. Trial-and-error from the attic, or a more certain arrangement from the roof. I'd definitely go the latter as attics are multipath nightmares and finding a "sweet spot" that allows you to get all the stations you want could be a maddening process. Or you could nail it first try.
Given the fact you have ALL those mountains around you, I'd say an attic antenna is going to be tough. You lose gain through the hills and from being in the attic.
Whatever you decide to do, keep receipts in case you have to return an antenna.
You're going to need at LEAST a mid-range UHF/VHF-Hi combo antenna
. Hopefully, someone more familiar with your area will chime in.
Were it me, I'd get a longer-range combo, slap a pre-amp on the mast with a rotor and put it on the peak of the roof. Rotor's only if you want to pull in Knoxville, too. I'd prefer to have the option.
Another thing to do is drive around and see what everyone else is using in your area. Remember, the higher the elevation, the less antenna they'll likely need.