I've been "doing this crap" for 40 years. Here's the skinny:
If your haven't already "bugged-out" when the excrement hits the rotors, you had better be willing to hunker down or have a tunnel to wherever you want to go. An outfitted vehicle will be a prime target. People can't even drive to work, without getting into or creating some form of gridlock. If even a single vehicle, two miles ahead of you is in an accident, stalls, or runs out of gas, you will be going nowhere; and, all of your provisions will become someone elses provisions, after they kill you.
Assuming you have reached your retreat-of-choice, where are you going to drive to next? Unless you have stored considerable fuel, where are you going to purchase any needed replenishment. If you were on foot and times were dangerous and hard, would you look for a vehicle to steal? If you could somehow use your vehicle, where would you get parts for repairs or replacements?
Outfit your retreat with the money you will save by not wasting it on some sort of "war wagon". If things go south, get out of town, long before the rabble. Don't tell anyone, and don't invite friends and family who are not already on their way. Have just enough fule to get where you are going, and just enough, properly stored, to get back, in the event things recover.
All this comes down to the items that will allow you to survive, WITHOUT THE TRAPPINGS OF SOCIETY. Autos are not survival gear. (It could be argued that a dirt bike might be functional; however, they can be heard for miles in the boonies. they are also mechanical and use [limited] fuel.
I used to kid folks by telling them that they probably weren't "suvivable" unless they could "live in a tree and gather nuts". That's a little extreme, but it's not a bad standard by which to judge your abilities.
(A word in your ear: For those who are stocking guns and ammo, don't. How many guns can you carry? How much ammo can you lug around. Are youir guns protected from the ravages of heat, cold, and moisture. Is your ammo properly stored? Have you even fired your guns, to see of they are functional or even remotely sighted -in? Even as trade goods, guns and precious metals will likely get you killed, before your time. [Ever been on a battlefield? There are guns and ammo all over the place. If it gets bad, let the idiots kill each other off, then sneak down and collect their guns, ammo, food, and "trucks".]