So I found the perfect place to take the family camping this year:
http://www.parks.ca.gov/?page_id=469
While a large part of Endor was filmed in Cresant City CA, Lucas did film some in the Redwood Forest behind Skywalker Ranch. This is only 6 miles from the Ranch and people can drive or hike up to an area where they have info boards and pic from filming the movie.
It's also nice because it's less then 1/2 an hour from San Francisco too. Fortunately it avoided the former governator's drastic state park funding cuts a couple years back.