There is usually a shortcut in many Meshtastic devices for immediately sending your location information to other users in the event of an emergency. The Meshtastic phone app has the ability to download local copies of some maps so you can pinpoint other people's locations. I realize that many people don't think that GPS will be useful after a major disaster, but unless the satellites themselves are impacted, accurate GPS signals will continue to be available for days or weeks after the supporting ground stations become inoperative, although the accuracy will begin to degrade over time. And GPS will obviously be available during shorter-term disasters like hurricanes, earthquakes, etc.

Another useful feature built into the Meshtastic ecosystem is encryption. The Meshtastic apps by default utilize a method of encryption called AES265-CTR, which is a relatively strong encryption not likely to be broken by anyone other than large government agencies. Groups of users can create and share 'channels' by sharing an encryption key, and while other Meshtastic devices on the same frequency setup can still pass messages on as part of the mesh, they can't read them without the key.

If you want to run a geographically widespread Meshtastic during 'normal' times when the Internet is available you can use the built-integration with a protocol called Message Queuing Telemetry Transport (MQTT). MQTT is a lightweight, publish-subscribe messaging protocol designed for machine-to-machine (M2M) and Internet of Things (IoT) communication, and it's optimized for environments like Meshtastic with limited network bandwidth, high latency, and potentially unreliable connections. The Meshtastic folks provide a public MQTT server available on the Internet (mqtt.meshtastic.org), and you can set up your own server (called a broker) on something like a Raspberry Pi on your home network. You'll also need at least one Meshtastic device that can connect to the Internet via something like WiFi. With MQTT you can integrate Meshtastic networks literally across the world, assuming the Internet is available. You can also use Meshtastic with MQTT to do things like send messages to devices on your home automation system. I don't have a lot of experience using MQTT with Meshtastic so I won't be covering it in any more detail. If you're interested check out the MQTT overview page.