I agree taking I40 west to I75 to I59 down south is the easy and pretty way to avoid Atlanta.
With the new bridge in Knoxville, just stay on I40, don't take the bypass. If it is rush hour, just stop at Camping World on the east side of Knoxville and browse for an hour or two to let traffic clear.
About the best place to fuel up is just before I75 heads south from I40. Big truck stops catching all of the I75 & I40 traffic.
2015 Ram 3500 4x4 Crew Cab SRW 6.4 Hemi LB 3.73 (12.4 hand calc avg mpg after 92,000 miles with camper)
2004 Lance 815 (prev: 2004 FW 35'; 1994 TT 30'; Tents)