I haven't tried lately, but a few years ago I tried using the APRS messaging and had these experiences (using a Yeasu VX-8R):
- - Entering a message was painfully tedious. Having some pre-entered messages would help, but even still.
- - Messaging through the internet (where a radio would pick it up and send it over the internet to another station for re-transmission) was hit-and-miss. Sometimes it would go through, sometimes it wouldn't, and sometimes it would go through over and over.
- - If you're in range to send an APRS text message, you're in range to talk on a voice channel (Which is much easier, IMO)
It might be that some digipeaters are up and running even if the rest of the world around you has fallen apart, but that's hard to predict. APRS messaging is certainly an option, but it's far from failsafe. But then, nothing is, really, so your comm plan needs lots of options that you and your family know so if one doesn't work, they know what else to try.