It's not just at your campsite, you can carry concealed on the way to your campsite according to 12026.2:
Also, while you are camping and within your campsite/RV/etc you are exempt from our concealed carry and loaded firearm laws.
Of course, 12025 is the list of concealed carry definitions:
12026.2. (a) Section 12025 does not apply to, or affect, any of the
(11) The transportation of a firearm by a person when going
directly to, or coming directly from, a lawful camping activity for
the purpose of having that firearm available for lawful personal
protection while at the lawful campsite. This paragraph shall not be
construed to override the statutory authority granted to the
Department of Parks and Recreation or any other state or local
governmental agencies to promulgate rules and regulations governing
the administration of parks and campgrounds.
12025. (a) A person is guilty of carrying a concealed firearm when
he or she does any of the following...
So technically, as long as it's okay to have a firearm in the park, then you can carry _directly_ to and from the campsite. Not sure if that means from your car to your campsite, or from your house to your campsite, or what. I'd probably take it to mean your car to your campsite.