This trail is well maintained and affords some of the most spectacular views of the Bay Area that you will find.  In addition, there are historical points of interest along the trail that speaks to the area's Quicksilver mining history.  It is well maintained and utilizes a series of switchbacks to get hikers up the steep side of the mountain to the visitor's center at the top.  It can get really warm in the open areas.  I would recommend getting an early start to beat the heat in the warm months.  There is a decent amount of shade on the trail which balances out the open, sunny areas.  Once you reach the summit, there are an additional 159 stairs to the visitors center at the top.  There is a covered area near the observation point which displays photos of the mountain's history as a Naval base and a sacred Ohlone ceremonial site.  The old radar tower structure still stands and is currently under renovation, surrounded by scaffolding (see photo).   The views from the top are spectacular.  Visitors take in four Bay Area peaks from the observation point;  Tamalpais, Diablo, Hamilton, and of course Umunhum.    On a very clear day, you can see San Francisco from the front side and Monterey from the back.  Morning fog often blankets the valley and Monterey views but, usually burns off by mid-morning.  Overall, this is a beautiful hike that is on the easy to moderate end of the scale.  Keep in mind that mountain bikes are also allowed on trails and dogs are not.  It has become increasingly popular and very well-traveled so, the later you get started the more challenging parking will be and the more people you will encounter on the trail.