I fished the Taylor, Pan, Gunnison, and various others in western CO quite a bit during my short stint as a guide. The river I miss the most is the Gunnison, but you have to do alot of hiking in there. The Taylor is frustrating but pretty fun. The Pan is pretty awesome. At either place youre going to want some small midges and nymphs as well as some Mysis shrimp patterns. I had success with something like this: