Great Falls is a popular destination for Albertans. They drive there for the shopping. Very cheap. Been there quite a few times, but mainly on my way to the Missouri River to flyfish. The fishing in the area is excellent and the trout are always rising. Cross the border into Canada and you rarely see a snout unless your a ninja fisherman (early morning/late night). My guess is that you are likely 1.5 hours max from great snowboarding and flyfishing.
.... Your close enough that you could do a B.C. and Alberta snowboard trip once a year if the road reports are looking good. And you have intercontinental ballistic missle silos to boot. I give it two thumbs up!
I honestly forgot that MT. was an excellent fly fishing region! That's great to know. Not that I have anything against an afternoon of drowning worms, but I have always loved the elegance and artful nature of fly fishing. Not to mention, fresh caught trout or steelhead on the grill?? Delicious!!!