If you are doing the bug bus tour combo with Alcatraz, make sure you have two days available. The bus tour gets validated and then you have 24 hours to use it. We only had one day in SF and as our Alcatraz tour was midday, we really were not able to use the big bus ticket at all. The bus route is 2.5 hours to do the full circuit. You can hop off at any time to explore but the bus runs in one direction only. So, if you get off at stop 6 to explore, when you hop back on the bus, it will take about 2 hours to get to the end. This is why you really need a full day. Also, you should request the Alcatraz tickets for either first thing in the morning or later in the afternoon. That way, you also maximize your big bus tour ticket. The Alcatraz tour was amazing but was only able to get on the big bus tour once. The stop locations were not clearly marked and as a result, the first bus passed right by me. Also, bus drivers were not that helpful or friendly. In general, I found the big bus staff unhelpful. I figured most of the stuff out myself or through my hotel concierge.