your best bet would be some A/T tires. i would say 30x9.5x15s or 235/75r15s. These are stock or close to stock size. The bigger the tire the heavier it is means more gas. BF Goodrich All-Terrain T/A KO BFGoodrich All-Terrain T/A KO
Or Goodyear Wrangler Silent Armors are good. Goodyear Wrangler SilentArmor
I have had both and either one is very good. I would say the BF Goodrich are the most popular though.
I have the goodyears on mine and they are very good on highway and light trail riding. Also very good in Snow.
215/75R15s i believe are stock size for Jeep Wrangler SEs. These tires are small but would give the best gas milage.