(Most of these apply to temporary disasters, not to SHTFs)
Take your important papers (deeds, birth certificates, bank info, etc). Make a copy of each of them. Keep the copy in a different place than the original (such as having one folder under the seat, and another in your suitcase). Make sure neither is in a place where it will fall out of the car every time you open the door!!
If you have some warning time, such as with hurricanes, pay as much down on your credit card as you can ahead of time. You don't want to hit your limit just as you're running out of gas. Also, have enough cash to fill the gas tank 3 times and to eat, as some places won't be able to take your card.
(Half the calls I got the day before Ike hit were from evacuees who needed to buy gas and were already at their credit limit. Fortunately the company had emergency policies in place to let us temporarily raise their limit if they were from the evacuation zone.)
If it's a temporary disaster like a major storm or hurricane, see if you can arrange to have your bank make next month's bill payments for you. Some will, some may charge a fee for this service. Trust me, if you're rebuilding your house and your mailbox is lost somewhere in the Atlantic, you aren't going to want the hassle of having your card declined because you missed a payment.
Be armed. A traffic jam makes for an easy target.
Leave the luxuries, take the necessities. You don't need a 67-piece gourmet cookware set. You do need food, water, and medications. This shouldn't have to be said, but it does.
Take a copy of your diploma or certification. If you can't go back home right away, you may need to make a new life where you find yourself, even if only for a few months.
Assume the majority of places you see along the way have been used by thousands of other refugees that day. That gas station might not have gas, they might be sold out of soda and potato chips. And there's a good chance their bathroom is out of TP. Bring as much food, water, and sanitary supplies as you can.
Know the back roads. Not just where they are, but how usable they might be. Some roads flood every spring. Some might not connect with where you're going. Main highways are more likely to get the attention of police and repair crews, but they are also more crowded. Weigh your options carefully.
Count heads after every stop. You wouldn't think this would be necessary, but if you're stressed and frantic it's easy to miss the obvious. This goes double if you have small kids who might be hidden by a blanket, make sure there's a kid under that blanket!
If possible take a copy of everyone’s medical records. if the strain causes a condition to flare up, you might need treatment at an unfamiliar clinic. It will help if you have a paper copy they can look at.
(I say “if possible” because my own medical records would fill half the truck. Use your common sense.)
I'm sure I'll think of more later, and I'm sure some of these could be debated, but I have stuff to take care of for now.
I don't worry about the deed, lawyers and the county have that.
Birth certificate? Nyet. Not worried about that either. I was born. I can prove that much. County has copies, as does Uncle.
Handy cash is important. It also makes you vulnerable. I keep an ace bandage in my go bag so cash and coins that clink can be wrapped up like a bandage on my body.
I think the most important points that you made is to observe what happened in the past and orient yourself to the facts at hand. Of course, one has to decide and act on that.
/johnny