Look up the tactics of the locals in "Starnaman" for another response, probably even more effective against the KFS soldiers.

Let's not forget that the KFS was written by its author to be undefeatable with realism a distant tenth in criteria. The KFS does not need a refit but replacement, a complete overhaul.

IMO, the Rich Five did not create one state but five, each one under the control of a family. (They do not want to share one state but will trade and cooperate with four others.) These states operates as a loose confederacy, engaged in trade and intrigue. These states cover parts of Kentucky, West Virginia, Virginia, Pennsylvania, and New York. The holdings of each state is (somewhat) intermingled with the others (similar to German Confederation or Holy Roman Empire) though each family has a predominate, primary territory.

The tech A, fusion power, listed in the book are not copies of fusion plants from MP but a single captured MP fusion plant originally intended to power the MP rebuilding in the future. After 150 years it's output is small and the R5 have moved to coal as a primary energy source.

No planes, no M1s, no Bradleys, no V300s because they do not need them, there is no large threat to their domain. They have several working MP vehicles which the "Secret Police" (more of a commando group than a police unit) use to ambush MP teams that they find.

Good point, if they can copy the fusion, they could copy an M1 exactly.