Starting at Jacksonville FL and traveling EAST, you would need to cover almost 21,200 miles in order to reach the longitude of Indianapolis IN. That's the main reason why folks from Jacksonville normally travel WEST for that particular trip, which reduces it to 269 miles.
266 miles taking this route: Take I-10 WEST from Jacksonville to I-75 SOUTH to TAMPA off EXIT 296A. Take I-75 SOUTH to I-275 SOUTH to TAMPA and ST. PETERSBURG off EXIT 274. Take I-275 SOUTH down to SR-60 WEST to CLEARWATER off EXIT 32. Take SR-60 WEST to Clearwater.
425 miles taking this route: Take I-75 NORTH from Naples to I-10 to JACKSONVILLE and TALLAHASSEE at EXIT 435 near Lake City. Follow signs on the exit ramp to I-10 WEST to TALLAHASSEE. Take I-10 WEST to Tallahassee.