Ive caught quite a few...but not by accident, i went out to bodies of water with populations of them and targeted them specifically...mostly in Rocky Mountain National Park. I usually try them in the summer and fall, by then most of the high country water is open and fishable. if you want some easier access to them try Lilly Lake in Estes Park...ive seen some pretty good sized ones there, although the lake gets lots of pressure and is kinda windy at times. In that lake i usually sight fish to cruisers with nymphs...ive had more luck with that tactic that with dries. (miracle nymphs and small Hare's Ears work well...as a dropper under a larger Griffith's Gnat) On the rivers ive done well with the usual summer time dry fly patterns....and especially terrestrials like hoppers and bee patterns. ive also had lots of luck with the good ol Royal Wulff...
they are definately a beautiful fish...worth the effort of a 5 mile hike if you are willing.