User blog comment:Gundam Legilis/Questions about Remnant/@comment-24891101-20140926004627

One presumes that humanity is not merely confined to four citadels and a scattering of villages. It's most likely that the Kingdoms consist of a network of fortified cities, linked by air travel and prior by heavily-defended roadways, with many fortresses along the way. The Kingdoms are probably nominally continent-filling, but the majority of that land is unoccupied and unprotected, so it is only national territory ''de jure. ''

Oobleck pointed to Menagerie on the map. Its political stability, as a relatively recently established de facto nation is an open question.

I think you're overanalysing Sun's situation. Where would Mulan and Thor grow up together? And anyway, there's a simple solution: He's from Vacuo, but goes to school in Mistral, hence he goes West (on a Journey) to Vale.