To get home from Santa Cruz you can put your bike on a shuttle bus that will take you to Cal Train in San Jose. It is $4.00 ride the shuttle. You have to bring two bungie cords to strap you bike on the bus.
Here is a link to the bus schedule.
The Shuttle will drop you off at San Jose Diridon station. It is $7.50 to get back to San Francisco on the Cal Train.
Here is a link to the train schedule.
This map of the trip has an elevation profile but cannot be embedded.
An additional map of the trip with an elevation profile.