The Trout Shop, Headhunters and Crosscurrent flyshops are in Craig (Crosscurrents has a shop in Helena, too), Montana River Outfitters is just down the road in Wolf Creek; pick your poison. I've only frequented the first 2 but I haven't heard anything bad about any of the shops; never found the need for a guide on the Mo (did find the need for better slack-line casting ability), but I could see where a boat would get you to some of the less-fished water. Hopefully, they wouldn't just have you bobber fishing the bathtub right below Holter; there's some beautiful country over there worth seeing. Again, if you haven't worked on your reach, parachute, puddle, bounce casts recently you might want to; those fish don't care much for drag. Have fun, catch a bunch.