Below you'll find a few ideas for your poster :) I'm pretty stoked on them, but please keep in mind these are just comps and not final versions. The more I played with your images, text and subject, the more I found myself trying to simplify things (since there is a lot to communicate). After creating a bunch of designs based more on the imagery you sent over, I went back to the drawing board (literally).
The only poster you'll see that I actually ended up using the imagery, is the last one. I'm using the "Badlands" landscape as an example of what I would do for all of the different locations. I also decided to stick with one color scheme, a muted red, white, and blue (vintagy tones to match an old map). Check them out and let me know if anything stands out to you. I know it's not exactly what we chatted about, but I just rand with the ideas that came to me :) Hope you like 'em!