@SBWB48 made a similar trip to SF last year that included a ballgame at AT&T (now Oracle Park). I believe she stayed at the Hyatt Regency near the Embarcadero or the Hyatt Centric at Fisherman's Wharf. If you have the UR points, transferring them to Hyatt can be a great deal! However, note that many of Hyatt's hotels will be going up in award categories on 3/18/19, including the Hyatt Centric Fisherman's Wharf (from Category 4 15k/night to Category 5 20k/night) -- so if you have dates in mind, book before then if you can. The Hyatt Regency (along with other Hyatts in the city) is already Category 5 20k/night and isn't changing. These two hotels are right along the Embarcadero, which runs along the city's eastern shoreline up against the Bay. From these hotels, you can easily walk to and catch the E-Embarcadero Line streetcar from Fisherman's Wharf or the Ferry Building down to Oracle Park, or the F-Line streetcar up and down the Embarcadero between Market Street and Fisherman's Wharf, or from the Hyatt Regency take the T-Third underground MUNI from Market Street to the ballpark. Uber and Lyft are also readily available, so there's no need to rent a car.
If you need more suggestions, let me know!
See
Hyatt 2019 Award Category Changes – 130 Increasing, 129 Decreasing (Effective 3/18/19)