Pemmican will last a long time. Properly dried grains(I choose zizania), nuts, seeds, will last almost indefinitely. Lots of raw honey. Food and water for at least a week, this will keep you functioning as comfortable as possible while you size up the situation and decide your course of action.
Food is important but chances are slim you will be able to store food for the rest of your lives. The most important thing to me is establishing relationships with people who produce food. They will no doubt be needing help in a situation like this, however they will feed their friends first. So, if you can, make sure you and your family are those friends.
If that is not an option, which in many people's case is the case. Learn how to take game. Be it fishing, hunting, trapping, foraging. Have a place where this is possible planned out ahead of time. Get to know that place, learn to love it, go there have a picnic or something. I already know where I would go. Easy for me because I live in Arizona, still I'm sure you can find a way to make it happen.
Skills are essential. If you form a tribe(good idea for various reasons), everyone will have to do something. Excel at something or many things, while staying flexible enough to do whatever is the situation calls for. Have something to offer, material and non material!!!
Guns are also a good idea. People who have not prepared could benefit from your preparation, if you do not prepare to defend your family. Scary thought, but nearly everyone had a gun on their hip less than 100 years ago in the place I call home. I still do on many occasion. Not paleo but necessary, no doubt.
