Creating an Empire - dealing with mutants, raiders, and elements of the old world.
Eventually every state wants to become a country, and then an empire. To do this, you need to go across the wasteland, and as the USA is very vast, it would take time, money, and patience. You would have to deal with the multitudes of mutants, military remnants, and raiders that travel the wastes.
I will assign a risk level to every un-occupied state. The risk level co-responds to the amount of mutants, raiders, and remnants in the area. moving into one of these territories counts as a war, and the risk level is the amount of years it takes to take over the territory, and the amount of hostiles in the territory.
Mutants are your number one threat, as most of them have lost their minds from the radiation from the nuclear war. They will never surrender, and always remain hostile. No matter what victory condition, they can never be absorbed into your country.
Military remnants are also a threat, as they posses advanced weapons and armor that many soldiers have not seen, or even knew that existed. They are usually more amiable than raiders or mutants. They survived by cryogenic preservation or just recruited or raised new soldiers.
Raiders are the least threatening, as they have no organization, and use improvised weapons to make opportunistic attacks. They are the easiest of the three to kill.
The risk ratings are coming.