Ohh.. La Jolla is a gorgeous area.
Congrats. I think forum member "ChanLuvr" (Or something like that.. doing this off memory) is from down there and may be able to answer your questions re: shops and rides.
At least to start with, take a look at: http://www.bikecal.com/ Has listings of daily rides and centuries. Not necessarily the most complete but it should give ya a decent list.
Welcome to CA!