If you played this map, you know: Map of the counties in the USA, there are 3066. Its a slow crawl to the east coast.
This map starts in WA and gets bigger going east. Like a solid wave... its too big to defog in one go. Takes multiple 10x defogs.

Here are my two suggestions, the first one most important.

- Start in the Middle. Center of Population indiana, perhaps. Have to weight the armies in each territory radiating out from the middle, of course.

- Perhaps Weight the armies in each county by population.

Thats my suggestion.
Let the trolling begin.
Doctor K