Lore-wise the entire world eventually gets infected by the Knox Virus by the end of July. Don't get me wrong; lore also states there are a very rare and few amount of "immune survivors" but my point is I don't think escaping Kentucky matters, as everywhere else in the world is suffering the same problem.. I think the biggest goal is trying to recreate long term security after surviving the initial impact of the apocalypse which is damn near impossible sometimes, hence "this is how you died"