The trail starts at Storm Castle Rock/Garnet Mountain Trailhead. From your car, head across the bridge over Squaw Creek and start climbing the singletrack. It's an aesthetic climbing experience with a handful of very steep and rugged sections, tight switchbacks, and obstacles to clear. Savor the views!
Once you end the singletrack, you can turn left and head up the old Forest Service Rd. to the lookout tower or you can turn around and let gravity take over. This climbing to the tower is very loose and will probably be more of a slog than an enjoyable experience. The views are worth it though.
The Forest Service rents the cabin out nightly, and it is well worth the experience.