I was up there last year in late June and had similar results. After I was done fishing, I chatted up the owner of the place I was staying (and fellow fly fisher) who said he's found the Dead and Kennebec that the fish aren't that well educated, so it's not so much what you throw at them, but where you're throwing it. I had just started tying my own flies at the time, and he said that my wooly buggers and other crude streamers fished as deep as I could get them would probably do the trick. I can't wait to get back up there and try!