I have spent more than a few days on the Powell from the VA border all the way to lake, and can say that the best days of the Powell are long gone unfortunately. Something happened about 7 years ago and the fishing went in the tank. The first thing is the amount of pressure went off the charts. Some idiots posted a bunch or reports and pictures from there on a couple of forums, the crowds descended on the river. It is very small and may not have been able to withstand the pressure.
The second major thing that happened was back to back floods during peak spawning, and those who have seen the Powell or know it at all, know it has very little good structure to break the current, and is almost a ditch. The recruitment was horrible, and thus numbers of smallmouth went in the ditch after those events.
I used to love the Powell because it was small, remote, and the fishing was worth the h***le of almost no take outs/ put ins. However, I spend maybe 1 day a year there anymore, and as most here know I fish for smallmouth almost exclusively from June 1 through September.
It might seem remote and untouched, but gets a ton of local pressure, and also people coming out of VA/KY to fish it as well. The BBQ joint also runs canoe trips daily on it, so the crowds can get out of hand quickly.
Not trying to be negative, but there are better places to smallmouth fish in this state other than the Powell IMO. If you are targeting redeyes, then it is loaded with them, literally more than anyone probably ever wants to catch in a lifetime.
Gary is right about the simplicity of smallmouth, I can go to the river and carry 2 flies, a spool of tippet, and nothing else and fish all day.
I am happy to offer any river advice you need, there isn't a smallmouth river in this state I haven't combed over more times than I can count, so if you need other info let me know.