Your approach seems pretty well thought out, and that is the approach I am going to use for the most part. The cell phone I have is one of those pay as you go cell phones, mine from cincinnati bell, which I discovered is not truly nationwide on my recent vacation. It was useless in Chicago, Dallas and Las Vegas. I should have stayed with tracfone, they are truly the only nationwide pay as you go cell phone. I do like the idea of multiple phone cards however, as in 9-11, new york cell service was out when the towers went down. The phone cards might have been useful in that situation as well.
Thanks for the ideas pizzaman!