We took a trip to the US for non-hiking reasons but baked this into our plans after seeing it in 105 Hikes as a half day trip.
You need to buy a Discovery Pass before parking at any of the usable parking lots, but then you can kind of build your own trip.
The forest here is lush and very mossy green like many Washington hikes and the lake is really nice, and not as cold as one might expect.
This isn't a premier hike and Stephen Hui (author of 105 Hikes) even puts it on his list of ones you could do on a rainy day, but I feel that would be a shame. Despite being a patchwork or roads cars could drive on, mountain bike downhill tracks and then just regular trails this trail has a bit of everything, and should be seen on a clear warm day:
-a scenic viewpoint (though it is from a driveable parking lot)
-lush green old growth
-a very nice lake