Best rules for large scale battles, running kingdoms?

[Jester David]

Paizo just released their Ultimate Campaign hardcover book. It contains rules for kingdom building and such. This may work for you.

I second this. It uses the same system that was in their Kingmaker adventure path, so it's been pretty heavily tested prior to the Ultimate Combat revision. The book includes building a city, managing a kingdom, and mass combat. But also small scale such as managing an inn or running a shop.
Plus, all the content is free on their website: http://paizo.com/pathfinderRPG/prd/index.html So you can test it out and see if you like it first.

 

[mattcolville]

The Book of War got pretty good reviews when it came out, as I recall.

http://rpg.drivethrustuff.com/product/691/Fields-of-Blood-The-Book-of-War?it=1