Rich--Thanks, and I certainly agree on the fact that browns are most active at dawn and dusk. I must say, however, that the thought of hiking out on the Tennessee side sounds daunting. For all that it is a backbreaker, at least the Big Fat Gap Trail has some switchbacks.
As for the rainbows, I'm guessing they came up from the lake. I don't know that I've ever fished below the lower falls, having always found that a good starting point (and the best fishing around and above Wildcat Falls).
Thanks for the info.