I fully agree on the smart phones. We recently did a cross-country trip that ended up as a roughly 5000 mile loop across the southern US, then up through the mountains starting in Albuquerque, and eventually back across Wyoming, and back down. A very large percentage of the time we could only make calls due to roaming agreements our carrier has with other carriers. But data wasn’t available (i.e. no Google Maps, no other internet sites, etc.). Picture messages were, of course, out of the question. And we’re with one of the better known companies. Once you get out in the wide open spaces (and we were on the Interstates almost the entire way), cell service for data is not like downtown big cities. I know some carriers are better than ours in that regard, but it was a real eye opener for us. So even if the cell phones are working, anything beyond a voice call may not make it at all.
And Tolik has a good point about bugging INTO an area where nobody knows you. That may not be a comfortable situation, to say the least. Planning is everything – and perhaps making contacts (and friends) with those in chosen areas would be a good idea ahead of time.