If you want there to have been a cell in Iowa at the time, Chris, it's possible. Let's just say coverage was spotty. It would kind of be hit or miss, but if you just happened to be close enough to a place where they decided it was worth putting in a cell, and if you just happen to have a good, relatively uninterrupted line-of-sight to that cell (no mountains or concrete buildings or anything like that in the way), you could get a signal. Maybe a spotty one, maybe not. Luck of the draw, basically.
As for call boxes, I can attest that they do, in fact, exist along certain lengths of I-95 and I-75. They were up early along "Aligator Alley" in Florida. It's a long highway which serves as the major connection between the east and west coasts of the state, but there's little more than alligator-infested swampland, two rest stops, and a native reservation (with the only gas station for *miles*) along the way.
Mostly, I've seen them in places like that. Places with little population, but along roads that connect major cities. They can't always maintain them for the entire length, but I've seen them every couple of miles for stretches of 100 miles or so at a time.
Paul
