The car is also a no go. The gun has to be in a locked container, unloaded, with no ammunition touching the gun, and out of reach of the driver. That's the simple breakdown of the law. "Locked" doesn't have to be much, though. My container was a regular, non-descript backpack with a little combination luggage lock and the ammo was in the outer pocket. There may be something about it only being lawful going to and from the range. Since I worked at one I that was almost always the case with me but I can't remember if that was an actual, obscure law or some stupid thing I heard some random idiot say. I have to look that up. Either way, once again the rules make it very hard to get to and use a gun in an emergency situation. It sucks. The people that wrote the laws had no grasp of the realities people face using firearms as a hobby, protection, or breaking the law.
Two more things for you to do. Go check out
www.calguns.net which is the local forum for the state and a book called "How to Own a Gun and Stay Out of Jail" which has a homepage here
http://www.gunlawpress.com/. Both of those are kept up to date with the latest legislation and all kinds of helpful info.
I don't know how experienced she is with shooting but I wouldn't recommend a small .45. It's been my experience that someone who can shoot their gun confidently is in much better shape than someone who can't. That means practice and most people won't do it (especially women) if it means using a punishing gun. These days a good hollowpoint will negate much of the 9 vs 40 vs 45 thing. Maybe a revolver she so she can get range time with 38 special and bump it to 357 magnum for home? Maybe a shotgun? You know her better than I do. Just my 2 cents.