Quick visit to San Francisco after leaving Yosemite to explore this notable town. Walking around the Northern end of the island will get you to everything you want to see quick. Though with the hills this city is built on, your calves will feel it later!
You can see Alcatraz from most vantage points that are high enough to see over buildings. Along with the Golden Gate bridge. Though of course both are reliant on the current weather keeping any fog out of the area.