Here are some maps that might help you,
http://api.ning.com/files/E0MpCkUxBh...lajollamap.JPG
http://api.ning.com/files/HOmFb*TSBz...vR/lajolla.jpg
To clarify, you park at the end of Avenida de la Playa and unload your kayak there if you don't plan to drive onto the sand. Leave your kayak on the beach, and go park at the parking lot. Walk back to your kayak (only a two minute walk). If you go there early enough (before 7AM) you might find parking on the street then you don't have to park at the parking lot.
I don't have much experience either but I have been there twice.
Good luck