When living and traveling in big cities it's easy to forget that network coverage in the countryside is a different thing. Some places are covered by one network while other places have better coverage of a different network. Too bad if you are expecting phone calls as you never know whether you will have coverage or not.
My solution: Have an extra phone and a prepaid SIM card of another network and set a "call forwarding when not reachable" from my main contract SIM to the phone with the prepaid SIM on another network. One of them will have coverage and calls are seamlessly forwarded to the second phone if the main phone lacks coverage. Perfect!
And for Internet access the second mobile with the prepaid SIM could be used, too. With an Android phone and Wi-Fi tethering, the main smartphone and tablet have a quick alternative should they run out of cellular coverage. Agreed, not a straight forward approach but when the network is not there, one has to improvise... :-)