We did something similar a couple of summers ago. Though I think we took a bit longer time than your plan, and my kids were older than yours now. Take a look at the below link.
http://www.flyertalk.com/forum/calif...alifornia.html
Generally, I think these are some of the sights/activities we enjoyed :
- Goat farm in Pescadero
- Santa Cruz Beach Broadwalk
- Tide pool in Santa Cruz (Natural Bridges)
- Elephant seal watching in Ano Nuevo
- Monterrey Bay Aquarium
We drove down mostly via Highway 1. While it is nice and scenic, it can also be rather long and windy, and also slow going. Just keep that in mind.