Most alpine lakes in Wa have been planted with trout at some point. If they have cutthroat, then they will usually be on the bottom, around large boulders or other cover, not too far from shore. Rainbows are less predictable, and spend more time out further and deeper in the lakes, while brookies are all over and usually easy to catch. Most of the lakes around the mountain loop hwy area have brookies, that might be a good place to start, although lake 22 had bows last time I was there. Also, mountain lakes can easily become fished out, since trout can't reproduce in most of them, except for brookies of course.