I imagine you'd want to stay fairly close to the beach most of the way, so I'd stick with PCH to Seal Beach, take 2nd Street/Bayshore down to the bike path through Long Beach, and get on the LA River Trail north (pick it up near the LB Aquarium).
Off the LART, going west on anything south of about Willow will take you through some pretty sketch areas. Willow and north becomes more industrial so not scenic but not dangerous. Pick your way over to Western, take that southto Palos Verdes Drive South and you're back along the coast. Then pick up the beach path through Redondo and Hermosa.
The bicycling directions available on Google Maps give you something pretty close to this. Those directions bypass the PV peninsula and keep you on Willow/Sepulveda all the way over to Hermosa, but I'd ride the extra distance for the scenery.
Last edited by tjh1960; 03-08-13 at 01:33 PM.