The Caney Fork is my “home water” – it is about an hour from Nashville, and it is the closest trout water to Nashville that is worth fishing right now. Good news is, the fishing on the Caney has been awesome this year.
The two primary flyshops in town are Fly South, (615) 251-6199, and Cumberland Transit, (615) 321-4069.
The entire Fly South store is devoted to fly fishing; Cumberland Transit is more of a general outdoors store with biking, backpacking, and other sports, but they do have a nice fly shop in the back. Game Fair, Ltd. south of town also has a flyshop, but I don’t know much about it.
Either Steve Nix at Fly South or Ronnie Howard at CT would be an excellent guide to show you some good fishing and be beginner-friendly for the gf. Steve is a certified casting instructor.