Funny you say that. I talked to a guy that floated the upper 1/3 of the river and they killed it on ISO dun, nymphs and rusty spinners. We floated the middle 1/3 and saw mostly sulphurs, caddis, olives, a few drakes and a few March Browns. We took our fish on MB nymphs, Snowshoe Sulphur emergers and March Brown compara-duns.
You know how it goes up there. One section is sick while everyone else is standing on the bank looking for bugs/fish. Now, on 5-13, I think the entire river was "on fire". That was one of the sickest days I've ever seen.