From Louisville, the last Speedway is in Bowling Green, KY. I believe there is a new Speedway between Nashville and Murfreesboro, TN along I24, but am not definite as Speedway is moving into the TN market.
We did the Kroger gas card deal for extra points and bought a mix of Shell and BP cards. BPs seemed more difficult to find. Shell seemed overly expensive at some exits. We stopped in GA at an exit with a Pilot and a Shell, Pilot was .30 a gallon cheaper.
I'll just stick to the Gasbuddy app and not limit myself to any particular chain, it's easier that way.