The Ring Mountain trail system provides some of the best views of San Francisco available in Marin County. From the top looking south, hikers can see the Bay Bridge, San Quentin, the city and many other treats.
Trails here are steep and moderately difficult. Rock outcrops along the trails are worth keeping watch, but the conditions on the trail are mostly smooth and clean. Dogs and trail runners are common, but so are tourists and those who don't regularly hike but appreciate marvelous views.
I recommend going slightly before sunset to catch the falling sun land behind the hills to the west. The best views here are toward the city and back to the east. The kaleidoscope of colors during a Northern California sunset are a sight to behold!
Ring Mountain has steep, but short, fire-roads with a few single tracks intertwined great for early morning/after work hikes. This is a good place to do some short trail running too, you should be able to link enough trails to get an hours run in before you get bored. Dogs are ok off-leash on the fire-roads as long as they are obedient and respond to voice commands. Some light bouldering can be done on Turtle Rock (a large rock towards the top).
Even though Ring Mountain is one of my favorites places to go (mainly because of location), I give it a 4 only because the amount of time spent here is limited by its small space.