McKenna, you make good points, as usual. But after Wilma, the landlines flooded out and died within hours, along with the buried broadband cables. The cell towers largely run for 36-48 hours afterwards, just on battery or generator, whatever they had. The backhaul? Was also buried cables, and some of that must have flooded out. Towers can be configured many ways, some actually direct traffic out in three different directions, with no hardwire connection to the backhaul. So depending on what the locals have done, they can be incredibly robust or incredibly frail.
The backhaul itself is another local issue. The internet, 20 years ago, looked like a big "H" that ran across the middle of the US with one leg up and down each coast. One break (like the Amtrak train that derailed in VA around 1999) and the whole Northeast went offline. Today? More backhauls, more backbone, and many businesses bring in two providers from two different service directions.
Utility lines in quake zones are often required, for some years now, to plan for that. The cables may be laid in a "Z" in the quake fault area, so that as the ground moves the "Z" straightens out and prevents a break. What LA has done, I don't know. But they did start the CERT program, and they did anticipate a total infrastructure loss, being one of the few major cities (counties) that tell their teams "When communications go down, self-deploy and begin SAR". I would not be surprised if they are ahead of the curve in many other ways as well, subject to the usual cost restraint arguments.
Will the cell system go down? Maybe. Maybe Goodyear will attach COWS to their new airships.(G) A truly big disaster hasn't yet hit, so no one really has planned a response to it. Except, after Mr. Bush got all educated about why he couldn't send the military in to respond to Katrina, they quietly (literally, secretly) slipped an addendum into the defense appropriations bill (about 6" thick, no one ever reads them all, I think it was 2006) which basically repeals the "Posse Comitatus Act" and allows the President to issue an executive order declaring a state of emergency (separately from the Stafford Act) at which point he's allowed to send in all military resources for domestic purposes--including relief and law enforcement.
VERY different from Katrina.
In any case...anything you can buy off a rack, is likely to be overwhelmed and useless. Anything that looks like it works, someone else may try to grab from you. The best bet? Right, pick a meeting place, and get out of Dodge unless you're part of the recovery teams.
And don't ask your carrier any questions about fuel or backhaul...they're liable to call DHS and say "There's a man asking questions..." and just get all paranoid about it. Even the routine maps (lie maps of the internet backbone) were pulled from most or all of the internet.
Much bigger more complex issue than which technology might work, I think we can agree on that. There's a lot that is simply not discussed, for fear of panicking the voters.