What about making a Korean peninsula map? Lots of zombies (especially in big cities), guns only at military locations (mil. bases, because of the gun law in S. Korea) in South Korea, and much more weapons may be found closer to the North Korea and/or the DMZ (the border).
Also, there’ll be a railway connecting cities in the Southern part of the Korean peninsula, maybe the same about the Northern part.
Or maybe there’d be just S. Korea, it’s up to you.
So, in general: tons of zombies on the map are present, custom korean-themed buildings (and custom for the northern part, if it’d be there, wich would look more like of a soviet style), not much guns in S. Korea, but plenty of them in the N. Korea and the countries’ border area and military bases.
Maybe there’d also be a subway somewhere?