First of all she will need her wetsuit, the water temp is going to be in the high 50s - to mid 60s.
In the LA area check out Mantattan Beach, Hermosa Beach, as you head North check out Zuma, Malibu and Latigo Point.
When you get up around the S.L.O. area hit Morro Bay, Pismo Beach Pier, Avila Beach, San Simeon Beach and Cayucos Pier.
Those are some of the main beaches, but tons more to check out as you drive the P.C.H, it's a beautiful - Enjoy your trip!