Kentucky Lake. Cabins right on the water in many price ranges or splurge and get a houseboat. State Resort Parks right on Kentucky and Barkley. www.kentuckylake.com or www.kentuckylake.org order the vacation planner.
Don't know exactly where you are, but I can see Barkley 3 hours and 15 minutes after I leave home, and it's all 4-lane from many places in Indiana. Probably about 5 hours from Indy.