There seems to be a lack of information on the trails/logging roads everyone rides around here. Post up what you know, whether it's just an ungated logging road or whatever.
It's just a logging road, but the roads around Pilchuck Falls off of Granstrom Road off of Lake Cavanaugh Road are pretty cool. There's a campground down by the river and there's a really steep hike down the mountain to a waterfall of sorts. If you go all the way to the top of the hill, there's a big gravel pit that's fun to mess around in.