Join Date: Jul 2007
Location: San Francisco/Sydney
Programs: UA 1K/MM, Hilton Diamond, Marriott Something, IHG Gold, Hertz PC, Avis PC
Posts: 8,156
There's an air-side bus. The trip itself is maybe 5 minutes, although the total time will depend on how long you need to wait for the bus to arrive.
There are signs within Terminal A directing you to the bus - it's hard to miss.