Well I drive a truck and it's basically my bedroom on wheels lol
I have a pillow, a blanket, about three pairs of shoes (which means I only have two pair that I swap between lol), four sweatshirts, three pairs of jeans, and two coats.
I also have "truck" things. I have a jack, a jerk strap, jumper cables, a trailer hitch, and a cell phone charger....even if the phone charger isn't really a "truck" thing.
Usually I have food type things in there too. I always have a bottle of water or Arnold Palmer in there and maybe a granola bar. Except I don't anymore because my mom yelled at me for how messy it was so I had to take the food out 'cause she said it was unsightly lol.
So yeah, I'm basically prepared to spend the night in a ditch somewhere or pull someone else out of a ditch or change a flat or jump someone or myself or whatever.