You're taking all weekend to do this, right? Cause you probably wouldn't make it in one day, even without stops.
For your first day, Wilder Ranch State Park just north of Santa Cruz has a short ~1 mile loop trail with some of the most amazing ocean-cliff views you'll ever see (made the top 10 hikes in CA list in a book I have). Parking is very close to the trail (small fee, but there are bathrooms), and you could do it in <1 hour, then have lunch in Santa Cruz and be on your way to Monterey, where you could spend the night.
Second day, see the aquarium in the morning, then hit the road for the drive to SLO. Carmel is a good spot for lunch.
After that, I don't know enough about the stuff out there. Santa Barbara is not that interesting, though, from what I remember.