Take I 5 to La Jolla (different exits, depending if you're going North or South).
Get to La Jolla Shores. To the South of La Jolla Shores hotel is Avenida de La Playa.
That road leads directly to the beach and is the launch.
Click the link below for a map:
http://www.ljshoreshotel.com/files/LJMap_LJSH.pdf