I know this thread is a month or so past, but hopefully still checking in on. We visit San Francisco quite a bit. My husbands family lives there so we go visit them a lot and plus he travels some their for work so we have stayed at various locations around the city. Honestly one of the best locations I felt we stayed in was at Parc 55 (a Hilton Hotel). It was right by Union Square, but located right by Powell and Market street to give plenty of transport options. You could take the cable car down to the Fishermans Wharf. Easily walk to Union Square. We actually one night walked to the Embarcadero and Ferry building one night then walked over to AT&T park on a whim to catch the baseball game. It is very close to the tenderloin area and a lot of panhandlers and homeless individuals around, but I never felt unsafe ever. I feel you see this throughout the city anyways. When we stayed in this spot my husband was there for work so I took my two young kids out in the stroller all day to various spots. We once stayed in the Embarcadero area when he was there for work too and I would avoid that if going as a tourist. Most everything around seems to shut down not long after work hours so it was pretty dead at night. We had to head out further to find places to eat that were open and things to do. We love the area and there is never enough time to do all we want to do each trip. If trying to see a lot in a short time one of those hop on hop off buses is great. We did that once when we brought a friend with us who had never been. Its a great way to get to go over the golden gate bridge and get pictures from the other side too then hit all the main areas faster. We actually have plans to head out there again this summer then drive down to ventura (my brother and sister in law are moving out there) then hopefully getting in a trip to Disneyland. It will be a 2 week adventure visiting family.