Portola Redwoods State Park is located near La Honda, CA and highway 84. It's $35 a night for vehicle campsites. There are plenty of sites for two or more buses to camp together very easily. There's a nice creek that runs through part of the campground and plenty of hiking trails. Showers and toilets are available.

I recently took the family camping here, along with several other families, and this is a great campground. It's beautiful, very well maintained and the facilities are nice. We had several kids in our group and they all had a blast. The place is a little out of the way and there are some curvy roads to navigate to get there, but I highly recommend it. We'll definitely be going back!

Here's a link to the website: http://www.parks.ca.gov/?page_id=539