How do I get there from the cruise port, how far in advance can I book on line. I have a ticket but need a reservation.

The cruise ship port is approx. 1 block from the flagship booth & boats. Walking distance. U can easily purchase tckt. @ ticket booth. Online if u prefer.

I got mine through Groupon, but I saw people buying it right then and there and hopping on the next one out

I used free app for free ride through city of San Diego. I bought my ticket at hotel desk a day in advance