The definitive answers are here:
http://caag.state.ca.us/firearms/index.html
If the gun is a long gun that is not on the "assault weapons" list, then you can haul it around, unloaded, all you want. Some cities (e.g. San Diego) have laws against "brandishing", which means you have to keep the gun out of sight, like in a gun sock or case. It need not be locked, though.
Handguns have to be unloaded and in a locked container, which includes a gun rug with a little lock on the zipper, or in the trunk. They just want to make sure you can't defend yourself. Again, "brandishing" laws may apply.
Unloaded means no ammunition in or attached to any part of the gun. It is not clear to me from the wording of the law whether a loaded detachable magazine that is kept separate from the gun constitutes a violation, but clearly the magazine could be called "part of the gun".
"Importing" a magazine or a gun that holds more than 10 rounds is verboten. This does not include a .22 or lever gun with a fixed tube mag, so a Marlin 60, Remington Fieldmaster, Winchester 94 Trail's End, etc. would all be legal, even though they hold more than 10 rounds.
Bottom line:
* No AR or AK based guns, or .50 BMG (similar calibers are okay, just not .50 BMG specifically).
* Long guns in general are not regulated very tightly, except those on the AW list
* Black powder guns are essentially unregulated, but they do count as a firearm if you're carrying them loaded, so relavent laws still must be followed.
* You can have a loaded gun in your tent, parked camper, and anywhere else you can legally shoot -- generally outside populated areas. This includes open carry of concealable weapons; the law specifies "carried openly in a belt holster".
* CA Fish and Game defines "loaded" as "one in the chamber". The State defines "loaded" as "an unexpended round attached to the gun." Hunting regulations and carry regulations are sometimes contradictory.
* Due to a long history of Latino gang activity in big cities, California has some arcane and draconian knife laws. Carrying a concealed knife above a certain size is a felony. Carrying a concealed, loaded pistol is just a misdemeanor. Some types of knives are illegal. See the page I posted if you carry a knife.
* Other oddball things are illegal as well, like dummy grenades. Go figure.
Welcome to the PRK. I'm thinkin' 'bout leavin'.