My dad is turning 60 next year, and I'm thinking about sending him on a trip somewhere in the US for a week of fly fishing. Right now he lives on the coast of SC and goes fishing 4-5 times a week on the rivers and creeks of the Low Country, so he has it pretty good. Crowded spots aren't going to cut it. He's been to Montana (5 years ago?) and absolutely loved it. Where else should I be looking?