The Ballona Creek Bike Path starts at Syd Kronenthal Park in east Culver City and extends about 7 miles to the Coast Bike Path along the beach. There is some free street parking near most of the entrances, except for Lincoln Blvd (11) and Marina del Rey (12).
Here is a map of all entrances, starting at National Blvd (#1) and the Pacific Avenue bridge (#13); below are maps of individual entrance locations. An additional entrance (#1A) will be built at Higuera St, about half a mile south of National Blvd, and is expected to open in 2016.
Note that the bikepath entrances are locked when there is a possibility of substantial rain. During rainstorms, the creek waters become fast and dangerous and may submerge parts of the bikepath