You're much better off at a downtown hotel. You're only a quick Muni ride to the ballpark from downtown. Fisherman's Wharf will mean a transfer.

This looks like a trip out of your own pocket. My advice would be to wait til you get closer, and just Priceline it. $50-$60 routinely gets a 4* hotel in downtown SF, sometimes the Hilton, Hyatt, Marriott, etc. All decent hotels, and at that price, a fraction of the traditional rates.