The weather during the dates you will be here should be gorgeous.
I highly recommend a trip to the Golden Gate Bridge if you enjoy scenery and want a good view of the City and the Bay.
Take a drive or walk across . Especially if it is clear out.
I personally avoid the Pier 39 area, as it is mostly a tourist trap. However a cable car trip up Powell over Nob Hill and down to the bay is great. But if you are adventurous I find it even more enriching to walk that same trek, so you can stop and look around every once in a while.
If you are a museum and park type person the De Young Museum and California Academy of Sciences are in a very nice part of Golden Gate Park.
I know the area you are staying very well, I live about 6-7 blocks away. You won?t encounter any problems, but if you like to be aware of your surroundings, the area between your hotel and Union Square is fine, and the area up the hill from your hotel (north) gets nicer and nicer with each passing block. The area south and west (slightly downhill) from your hotel gets grittier as you go. The neighborhood just to the west of Union Square is the most dense concentration of humans in the US outside a few zip codes in Manhattan.
As for restaurants and bars, there are so many it?s hard for me to recommend just 1, but if you are looking for a particular kind of food (upscale, hole in the wall, particular ethnicity etc.), or particular atmosphere in a bar (from drag shows, to sports bars and anything in between) I could definitely make a few recommendations.
