This trail goes past (or has views of) all the big tourist sites for San Francsico. Downtown, Embarcadero, Pier 39, Fishermans Wharf, Fort Mason, Marina, Presidio, Fort Point, and the Golden Gate Bridge!
If you are visiting San Francsico, or you have friends visiting, this is the trail to ride. The southern end is ATT park, home of the SF Giants. Going north the path passes right on the bay and ender the Bay Bridge.
The Southern section of the trail between King Street and Beach Street, is a wide sidewalk on the east side of Embarcadero. On a nice day there are too many pedestrians to bicycle the sidewalk, so use the bike lane in the road. Just to the east of the Embarcadero is downtown, then Chinatown, and the Italian North Beach neighborhoods. Lots of great bay views on this section.
Between Bay Street (pier 39) and Hyde St (aquatic park) there is no trail or bike lane. Beach street has relatively low traffic for the on street connection, or possibly North Point st. This section passes by Fisherman's Wharf.
After Hyde street ride through the Aquatic Park, and after Van Ness a trail roadway right along the bay to Fort Mason. This section has excellent views of the bay, Alcatraz, and the Golden Gate Bridge.
Next ride along the marina green; a big grassy area with lots of people enjoying the outdoors.
After Baker St, enter the Presidio, a former army base, now a large park. There is a paved trail along the road, or a earth trail next to the bay, with grasslands and wet lands in between.
Continue all the way to Fort Point right underneath the Golden Gate Bridge. If you still have energy, go up the hill and ride across the bridge, (it has sidewalks).
If you are visiting San Francsico, there are shops in the Fisherman's Wharf area that rent bicycles along with a map for how to ride the Golden Gate Bridge.