See San Francisco from Sonoma County! The book  Treasure Island by Robert Lewis Stevenson is a favorite in our home. With two boys, who could go wrong with pirate stories? So it was strangely odd that our family had not visited the state park so near to our home named after Robert Louis Stevenson.   Driving up  St. Helena, I would suggest packing empty water bottles. It is so much fun filling the bottles from the natural spring on the north side of  St. Helena  Mountain . It takes some time but the water tastes so good! Once you arrive at the top of the mountain parking can be tricky, so carpool if you get the chance..   The hike begins on the west side of Highway 29 at the Stevenson Memorial trailhead. A few steps bring the trail up into a small grassy meadow dotted with a few picnic tables, and then the climb begins through dense. Author Robert Louis Stevenson and his wife spent their honeymoon here, sleeping in a decrepit old mining building. Stevenson's slim memoir, Silverado Squatters, is a vivid description of their adventures. Just past the memorial you will see, the trail becomes steep.   On a clear day you will be surprised at what you can see from this peak. I was able to see monument buildings of  San Francisco and  Lake  Berryessa . Just a gorgeous view! Enjoy a picnic while watching the world around you. And when you are ready, you can start the trek back down the mountain. The nice thing is that the end of the hike is downhill. It took us about 6 hours to complete the hike. Be sure to give yourself plenty of time to hike, explore and picnic.   More information: Mount  St. Helena is the Bay Area's highest publicly accessible (by trail) peak, topping out at 4,304 feet. This trek begins uphill on a short, eroded trail, then continues to the summit on a long, sinuous, well-graded fire road. There's very little challenge here, just a steady climb to the top, where views unfold, spanning the distance from the  San Francisco skyline to  Mount Shasta on a clear day. Location: 7 miles north of the town of Calistoga on Highway 29, and roughly 50 miles north of the San Francisco Bay.  Distance, category, and difficulty: 11.2 mile strenuous out-and-back. Not for little kids. Exposure: Some pockets of shade, but largely exposed. Trail traffic: Light. Trail surfaces: Dirt fire road. Hiking time:6 hours - all day  Seasons: The best seasons are spring and fall. Trailhead details: No fee. No facilities. Side of road parking in small dirt lots. Rules: Dogs are not allowed on the park trails