As I read the law, until you get to your campsite, your handgun (pistol or revolver) needs to be unloaded and locked in a container and no ammo attached to the weapon in any way in California. This is convenient if you are travelling by automobile. Just don't break out the gun from the box until you have arrived at your campsite.
Some campsites specify that firearms are illegal there however, such as in state and national parks.
So unless you are camping in a USFS or BLM area, you may not be able to break out the gun at all.
If by wilderness you literally mean designated wilderness, then this is covered by USFS boundaries.
If by wilderness you simply mean the outdoors, then it depends on who has jurisdiction over these wildlands.
Carrying concealed anywhere in California requires a rarely issued permit. Thus you cannot carry concealed anywhere in California without the permit.
You may carry openly and loaded or unloaded anywhere that shooting is allowed. Again, we are back to USFS and BLM areas only.
Thus when you are hiking or hunting in USFS or BLM lands in California you may open-carry the weapon in a holster, loaded or unloaded, just like back in the days before then-Gov Ronald Reagan suspended that "privilege" due to the militancy of The Black Panthers in 1968. Who said Reagan did not have some communist tendancies of his own? There is proof.
If you are hunting, make sure you brought a hunting license with you, at least. Otherwise your story won't add up.
http://www.allstays.com/Features/california-gun-laws-travel-guide/
