Used to live in Knoxville and had a chance to visit all these fields.
My favorite spot in the area was Hiatt's Game On Paintball
, which is about an hour north of Gatlinburg (Smokey Mountain Paintball is a little closer- about 35 minutes northeast).
Hiatt's is an amazing place, and probably your cheapest option, but tends to focus mostly on single-day scenario events and preregistered groups.
HKArmyKid219, when are you going to be there and how many people will you have?
Also, don't miss Dollywood while you're in Gatlinburg. Wild Eagle and Mystery Mine are amazing coasters.