One initial Idea I had would be Canbre,Australia because they could also have been dealing with a chinese invasion, in Darwin (like the US were in alaska) and could of annexed New Zealand in an attempt for power also this could mean new weapons and apparell along with tribes and armies both influenced by aborigini, British Empirial and modern day australian culture and polotics.
Another Idea of mine was to have it set in the penines (a series of mountains in england) particually around an area called the ribble valley, a valley with many towns and villages like a large town called cletheroe and is right between 2 main british cities Preston and Blackburn these two cities could be the capitols of two small nations (some what like city states around 500bc) one the prestonian empire (preston) and the English Northern Republic (blackburn). The region has unique culture because its positioned right next to the Lancashire/Yorkshire Border using combinations of dialects from both english counties. Also raiders could be like British Highwaymen of the 1800s using handguns (sawed of shotguns) as a primary weapon. Also with it being english this could have influence from many ages such as medieval, british empirial , Edwardian (early 1900s- world wars, and colapse of the british empire and modern british culture.
