The Mount St. Helena Summit Trail is primarily a fire road which climbs up the up the south-facing slopes of the mountain. The trail can be accessed either from the pipe-gated fire road entrance located ¼ mile east of the Highway 29 parking lot or by taking the Robert Louis Stevenson Memorial Trail. As the trail is an access road to the many communication facilities atop the mountain, it is well graded and smooth, making for a perfect gravel grinder. It's worth noting, however, that the trail affords very little shade.
Once on top of the mountain there are trails leading to the north and south peaks for different vistas of Northern California. From the parking lot to the summit is 10 miles round trip and has an 1,800 feet elevation change. The views are well work the work as it's a true top-of-the-world experience.