Key with me. My pack has a clip for keys. Cash. Never know when I have to bribe someone for a ride back to my car if I bail out at a different trailhead. Drivers License and credit card, in the first aid kit.

My car is old and trashy. I doubt anyone would want to steal it. My bigger fear is that the car will not start due to some mechanical problem after sitting at the trailhead for weeks. I leave a small amount of cash in the glove box. Sort of tricks a thief into not looking further.

Food and cell phone are issues. No food can be left in the car due to bears, but I like to have some emergency food. I have an old Garcia bear can, so I put the food and toiletries in it and set it near my car. I have never had any trouble with this. I hide the cell phone in the car. Problem is that often I cannot remember where I hid it! When I get home I have to call my cell phone to find it.