Glad to see someone really knows that its not that easy to cut down power to all world, and shut down internet. All talk about WWIII, I think it wont be anything similar to previous ones. Europe, North America and especially Australia should be rather safe to live in next decades, wars will be fought as now, Middle East and Africa.
Not sure about the geography. In all probability, the United States will be one of the main belligerents in the WW3. Canada and Australia are some of the most loyal allies of the United States, and so are most of the Western European nations.