Howdy,
I lived on Orcas for about a year, and regularly fished Cascade, Mountain, and Twin Lakes when in season. Did alright on Cascade and Twin Lakes, but didn't ever seem to move many fish on Mountain Lake. There was a private lake on Orcas that a friend took me to once that was amazing, but I would only fish that one with permision. I fished out of my float tube and regularly caught trout using nymphs, hair's ears, pheasant tails, egg imitations, and some spinning gear. Best of luck and have fun dodging all of the bicyclists. Andy M