Three Creek Lake is going to have a good week I suspect with the warmer days coming to Oregon until next weekend. Beetles, Ants, Hippie Stompers, Leeches, Scuds and Mayfly nymphs like a Red PT Jig or CB Cate Jig.
Also make sure to get a Hot Orange Beaded Olive Wooly Bugger or Damsel Nymph for the rest of the season. The Brook Trout are mad at that fly if you know what I mean.