Spring? Holston. Why? The Holston is a blast in the Spring with all the caddis. Who? Hugh Hartsell (because Hugh knows that river) or Tim Doyle would be good choices. But, considering what you're looking for, wanting a broad experience, I would say wait and fish the South Holston during the sulfur season. Why? I don't want to go into a lot of details and post photos but let me just say that it's something you'll want to experience. Who? Scott Lewis (Alpha Trout Outfitters) Scott knows the river like a brother. He has a Biology degree and is always on top of what's going on up there. Want to go with someone that will teach you just about anything you want to know about flyfishing and have a trip that rivals just about anything in the country? This would be the one for you. If you really watch what's going on you won't believe it.
The South Holston has been dubbed one of the most techincal tailwaters in the country by many folks.
I guide but I had to leave Tennessee last year to help my parents out. Scott would be my number one pick for something very much out of the ordinary.