Started off the newyear with a snowshow trip on the Cooper River trail. A cold, clear day, with temps in the 20s and intermittent fog.
The road up from Rosyln/Ronald was clear of snow but often covered in ice, so going was fairly slow. We were a little confused about where the trail started. Basically, there's a turnaround a the end of the plowed road. Once you hit that, turn around and park at the parallel parking area a couple hundred yards back. If that's full, there's parking on a spur road a little further. Then walk back to the turnaround, and straight through on the groomed path, over a bridge, etc.
The groomed path to the summertime Cooper River trailhead was well-packed; would work fine in cross-country skis or just boots as well. The grooming stops at the trailhead proper, but there was a well-trod track from previous snowhshoers to follow. Of course, one good snow and that path could be gone, and the trail wouldn't be super-easy to follow without it. Apart from a few loose patches of snow on sloped places, no major impediments.
The trail is mostly in the woods, but you get intermittent views of some lovely mountains in the distance. Seemed like we were climbing more than the 400 feet listed in the guide, but still not too steep or strenuous.
We had to turn around after about 3 miles as it was starting to get dark, so we didn't make it to the lake. While this was a longer trip from Seattle than we expected, it was a pleasant hike that I'd like to do again some time with more time.