You might be chasing up the wrong pole looking for summer runs, but there are a few other runs that are worthwhile in the Nooksack nonetheless. I've spent a few years chasing them, as I lived in Bellingham 14 years.
The Mosquito Lake Road bridge the gentleman above mentioned is a good spot--both for silvers and chum. Fish the little upstream side channels, too--often fish will hold en masse in deeper little riffles. Kings spawn in those channels when the water's low--avoid disturbing them. Hit silvers there with spoons and Blue Fox spinners--or around some of the log jams above and below the Hwy. 9 bridge (a little downriver). There's a nice parking area there, and plenty of bank access, and look for chums galore dying along there in December. Steelies have been planted in the Middle Fork, although access and run timing are things I'm completely oblivious to (as evidenced by several unfruitful forays there). Try the area below the Middle Fork bridge; Trout Unlimited (I think) has a little hatchery operation in there somewhere. Again, beware fish spawning in side channels--dark ugly silvers may be here and there. The Kendall Creek hatchery has never been attractive to me--but the mouth of every little side stream below has been...
Look up the North Fork road if the water's still high--often smaller holes in that gravelly section will hold fish--ie, the mouth of Racehorse Creek.
I spent a lot of time plunking the lower river, too--mostly on River Road, which is off the Guide Meridian near the bridge. There's a few nice gravel bars along there, and silvers all over on the bite if the water's right. Siltation from logging and effluent from manure ponds will be your biggest enemy downriver. Even during dirty water, though, when the silvers are in, every single one of them will poke its nose in water from the mouth of Fishtrap Creek...
Above all, don't get discouraged. The Nooksack can be a beautiful place to fish, even if the catching remains generally lousy. When you do catch a fish, keep fishing the rest of the day and the next and the next. One season I filled up two and half punchcards of silvers sitting on the same rock. (Wouldn't you know, the following season I never touched a fish there...)
Tight lines!