I just joined TN Bass Fishing and if if you are still looking for good rivers to float in Middle TN, look no further than the Caney Fork. One of the best trout fishing rivers in the Eastern U.S. stocked with rainbows and browns but this isn't the steam you are visualizing in the smokies. Smallies, stripes and other bass are common in the summer months. The trout can get quite big easily exceed 24" for rainbows and 30" browns. It's a beautiful, wide river and is located near Cookville, TN
The river is the tailwaters of center hill lake so the river flow is manage by TVA and never exceeds 52 degrees so you can catch trout year round. The river is wide with few shoal areas or obstructions. You can float it without a generator going at the dam but 1 generator is preferred as it really makes the fish active. Start at the launch at the dam and paddle up to the dam and fish it for awhile as there's a lot of really nice fish there. One generator gives you a nice constant flow so you won't have to paddle much but you can slow down easily to fish certain areas. For a 2-2.5 hour float, pull out at Happy Hollow Boat Ramp. For a 4-5 hour float, you will want to pull out at Betty's Island. You will obviously need to drop a car at your start and end point.
I do a lot of business with Caney Fork Outfitters and bought my Jackson Big Tuna from them. Good people. They make a living on this river and know it very well. Seek their advice before going (fishing report, river levels, generation schedule, etc.) They have a fishing report on their website too. http://caneyforkriverrunners.com and provide a shuttle service if you are by yourself. Also, don't let the picture on their website start page scare you. This is not the Caney Fork river but nearby Rock Island - a hot spot for the "play boaters". The TVA's website also has the generation schedule for center hill posted 24 hours in advance.
You will catch some nice trout with little Cleo's, inline spinners (rooster tails), etc. For one generator, go with a slightly heavier so it will get lower in the flow. I caught 13 trout in 2 hours three weeks ago. All were over 13" and the biggest being a 17" brown. I also catch a lot of smallies in this river on wacky rigged worms and crank baits but they seem to be a little further down from the dam. The entire riverbed consists of river rock and gravel.
As with any river, don't take any chances. I wouldn't never go down the river if it's high or if there's more than one generator going. Plan ahead and you will have a blast. It's a special place. Let me know if I can help.