Pleasant, quiet, and comfortable
This campground isn't directly on the West Fork of the Dennison, but it's an easy 1/4 mile walk. The campsites each have picnic tables and fire rings and you'll need to bring your own firewood. There are individual campsites in the upper part of the campground, and there's a parking area for RVs, with an accessible pit toilet, just below. It's probably a little far from Chicken for people looking for tourist activities but it's a lovely place to stay a few days.
Because I was there as early as I was, the grayling fishing was okay but not spectacular. The fish were skinny (winters up here are very long) and you had to fish pretty deep to find them.
I was there in May, and weather blows through the 40-Mile country very quickly - it can be a bit unpredictable. We had snow at one point. Parts of the Taylor Highway can be a bit sketchy, particularly early and late in the season, but the section between the Alcan and Chicken tends to be in good shape and highly driveable.