let's see.   Arriving 8 am and you want to rent a car?  given the time to rent and return at SFO, you'll be better off taking bart up to the city,   Take it to embarcadero.  Get off head east to the ferry building.  There's food, shops, interesting things there (as well as some history), wander up along the piers, crab is still in season, so there's a snack there.  Jump on the F market train (they are old, reconditioned trains) ride that up to church (about 30 minutes).  At this point you're a short distance from the toronado (pliney is on tap) or you can walk up haight to magnolia.  It's about an 15 minute walk.  Magnolia's in upper haight.  Eat, have samplers.  At this point you are a short (15 minute) walk to golden gate park or just leave magnolia and grab the bus (#43) to union street/marina.  wander around that area and take the 42 bus down van ness to the train station.  21A is about a 10 minute walk from the train station - check out pacbell park.  Red's Java Hut is close by as well as some art on the embarcadero.  After 21A walk north on 2nd street and you are back at the montgomery bart station.  Take bart back to the airport and all is good.
total cost on bart/muni probably $13 per person.  Parking in SF can suck if you don't know where to park.  Traffic between the airport and the city can really suck.  California drivers suck.  But money isn't everything.  You are tight on time, and if you know which bus/train/subway to take, you can jet through the city pretty effectively.
Ohh..  if you really feel ambitious, you can check out SF brewcraft on clement.  it's a classic HB shop.
				
			

 


