A slightly new (or old?) route variation as suggested by Erik.

Out to Malibu Beach for the usual break on Clear Creek. People who want a short route can turn around here. Otherwise, up Malibu Canyon out to Calabasas and parallel the 101 on Mureau and Calabasas Roads. Back over Old Topanga to PCH. Full ride is 53 miles with about 2900 feet of climbing. See https://ridewithgps.com/routes/29229538 for a RideWithGPS view of the route.