Consider setting aside one or more Raspberry Pi 3 computers. They run on 5v and have a complete operating system with compilers, web browser, word processor, spreadsheet, database, etc. Combine with references on USB drives and we are much more quickly on our way back to civilization. Note: The Raspberry Pi needs a USB keyboard, USB mouse and any screen that takes HDMI for human interface. You do not need a keyboard to run it as a server (web server, file server, communications device, etc.) Applications to connect to the server, control it and program it are available for Android and iPhone (phone service is not needed, the Raspberry Pi can be the Wi-Fi server for the phone to connect). Essential – make sure you have set the device up how you want to use it and have tested it in your End of the World configuration before you need it. – T.R.