It looks like you're seeking a technical solution to a social problem. If there's no stable society, all the tech in the world is useless. The key is to have a

It looks like you're seeking a technical solution to a social problem. If there's no stable society, all the tech in the world is useless. The key is to have a circle of friends who you've worked with in the past to route around problems like natural disasters, societal failures, accidents, etc. This is your local community network. If things go bad, who can you count on, and who will count on you? Technology that would be useful in a local failure of society would be centered around distributed communications and logistics. Perhaps setting up stand alone mesh networks with a small server to help coordinate activities would be quite helpful. Look into the ways people help in the disasters that already happen, and you'll likely find things to lend support towards, and/or adopt for yourself.