I just got back last night from a week on the North CDA. As mentioned, the floaters are pretty thick during the week and insane on the weekends in the lower stretches. Even so, if we had stayed a few more days, we would have moved further down river because the fishing was not great in the upper reaches.
That was our first time there and thinking we could get away from some of the crowd, we headed higher because for me, the more remote the better. A lot fewer people up there. We stayed the first couple of days at Big Hank. Caught a few small cutties, but had to work for them. Saw a moose in the river, which was cool. Moved up to Teepee Creek the last few days. Some really fishy-looking water up there but not outstanding fishing. Those you do catch are beautiful cutthroats, though. My thinking is that much of the larger population may have moved lower in search of more water because it's getting thin up higher. On the way out, we followed Teepee Creek upstream over the mountain and down to the Little North Fork. We didn't fish it but that looked like some decent water, as well.
As mentioned, The River Fly Shop was a good source of info and flies. The Snake Pit next door is worth the stop for lunch and a brew; lots of history there.
PM if you want more specific info on where we found fish.