the Culver City trail
Nice Marina ride, up the Culver trail (very easy), through Culver City, Century City, Santa Monica and back to Marina del Rey.
We did this one the first time on 8/11/02 in 2:21:32. Best guess on distance is 29-31 miles. Its very easy for the first hour, there's really only one hill (Motor Ave... it's a steep but short), but the pavement is good to very good.