The names, that is something to discuss.
I like the way of FATW, example: Riders of the Riddermark, and so on.
Theoden ask his men in the film, when he rides to the Army: Where are they riders of the White Mountains or something like that. I only know the german version of the films.
This could be an Idea for the Names and mor Rider Units.
Riders from different Areas of Rohan.