Originally Posted by
Lost
Agree with the above that the Santa Cruz area would be the place to look. Plenty of activities to keep the little one occupied for a few days. Off the top of my head:
-Santa Cruz Beach Boardwalk
-Monterey Bay Aquarium
-Roaring Camp Railroad
-Mystery Spot
-Gilroy Gardens theme park
Also pay attention to the temperature forecast and pack accordingly when you get close to the trip. The coast can be around 60°F/15°C while just 20 miles inland it could be around 85°F/28°C (or warmer) that time of year.
My emphasis on two things most six-year-olds would love. Then again, the SC Boardwalk is not much different than small amusement parks elsewhere. The MB Aquarium is extraordinary, however.
Would you be up for a sea kayak adventure, OP? If so, I strongly recommend renting one at the Elkhorn Slough, a short drive north of Monterey:
http://www.elkhornslough.org/visit.htm You will likely encounter dozens or even hundreds of sea otters, sea lions and seals. The water in the slough is calm, so you need not be an experienced kayaker.