I love San Francisco! I agree that Union Square is the best place for you to stay because not only is it within walking distance of many places, but you'll have no problem getting the cable car or many taxis there to go down to the wharf and elsewhere.
The Alcatraz night tour is fun (definitely order tickets ASAP), and there are so many excellent restaurants. One of my favorite things to do is go to tea or cocktails at the elegant St. Francis hotel in Union Square. I also love the great shopping in Chinatown - jewelry and fine linens galore. Oh, be sure to get a sundae at Ghiradelli's
