Re: Sheridan Wyoming advice
Every August I fish the Tongue which comes out of the mountains just west of Dayton, WY, with Dayton being 18 miles NW of Sheridan. I have no experience with guides, but I ask advice from the Fly Shop of The Big Horns right there in Sheridan on main street, and I always seem to get great advice.
I don't know what kind of fishing you were thinking of doing, meadow versus canyon, but if you go up in the mountains it can always be cold, even in July.
If you like to golf you're in the middle of the best golf courses in Wyoming.