I am running late on posting here. What part of Clarksville. I am on my way back there come later this month. I will be off of exit 11.
Check into Lake barkley, and Lake Kentucky out at Land Between the Lakes. Great sposts all over there. Just take route 79 down into LBL. http://www.lbl.org/Fishing.html
As for right there in Clarksville, the Cumberland river produces some good bass, and some very good catfish.
Hope that gets you going in the right direction.