I got a old wood army box filled with stuff and some side compartments. After seeing some of all your setups Im gonna add to it a bit and put my 3 day pack with it. I have a wife, 15 month old daughter and a chocolate lab. I have been stranded a few times, and after a family got lost in a park in oregon, in their car, in the snow for a week or so. They burnt tires to stay warm and the dad didnt make it. Things can happen. With their story in mind I try to stay prepared, specially with a family now.
I got a first aid kit and 2 6x4 tarps in the back of my Runner, with the Yota tool kit. Usually have a few blankets laying around in the back seat for the dog too. Being an (idiot

)lab she will dive in just about any body of water.
My box is strapped in with a CS kukuri machete and a CS Trench hawk under the strap.
Box Contains: (what I can remember)
Hammer, pliers, channel locks, wrench, Rope, Para cord, matches,
Gorilla clue, nails, flare, lighter, fire started
Coffee, cliff bars, dog food, water filter,
Poncho, extra socks, Soap, Sewing kit, .22lr, 12ga, 40cal, .38spl
Im gonna take a pic and add to it later and ill update here.