I do all of the above except for the longer leader. I do tend to downsize tippet in the fall when the water gets low and clear but also fish all the water, not just certain sections. As to fly selection, I tend to fish whatever I feel like throwing that day which can range from dries to nymphs to streamers. Most of the time, if I find rising trout I will throw dries (usually BWOs in the fall). If I'm tossing a searching pattern dry, it will usually be an orange EHC since the Smokies are in Vol country.
For nymphs, it can range from a large Tellico to a small BWO or perhaps a BHPT or Copper John. For streamers, don't overlook small ones (#10-#12). Fish them with lots of action in all types of water. Kelly Galloup streamer methods are also very good but it can be tough throwing sinking lines on the small to medium streams of the Smokies. I tend towards floating line and putting weight in my streamers to get them down... If you want to master fishing in low clear water, find the fish first. Work a fish until it either spooks or you catch it. Watching a fishes response to your offerings will be one of the best teachers you can have in the Park. Some of the most selective fish I've cast over have been 8 inch rainbows. Sight fishing of any type will hone your skills...it doesn't have to just be to large fish.