My family and I spend alot of time on the Denali Highway camping, kayaking, and fishing, here is what we have found. A packraft or kayak is the optimal means to enjoy these streams in full, or walking works too if your energetic.

Rock Creek to Tangle Lakes
; alot of Greyling the last half mile before hitting the lake, Lakers, and Burbot present where the creek dumps into the lake. (class II-III whitewater)
Windy Creek; decent fishing above the canyon rapids, no pools in canyon to speak of, one decent pool 200 yards above Valdez Creek Mine Road. The creek is swift and harder to fish than others in the area, our best fishing was at the bridge on Valdez Mine Road. (class III-III+ whitewater in canyon)
Valdez Creek; Fishing good where it crosses the mine road, but they are fished and shy. The lake upstream is pretty good too, but in between the road and lake is fierce whitewater. (class III-IV whitewater in canyon)
Brushkana River; the best of the lot, we run the whitewater in kayaks and packrafts to the many deep pools below. Take note, we are poor fishermen, the family and I that is, but we still catch over a hundred everytime we go, just slinging lures at them. A good fly fishermen would find it no challenge and quickly would become bored. I would say the fishing is on par with the Delta but I think the greyling are larger, on average, in the Brushkana. (class II-II+ whitewater to reach pools)
I have a youtube, in the kayaking section, of a Brushkana trip with my kids.