Slough Creek update: I added some of the rocky areas. I used the 1983 map as the base. I scanned the map in and adjusted it to fit as best I could, then added the rocky ground. I suspect it'll need some tweaking in the field.
And while I was doing that, I was also running some lidar through KP for the national forest near Halsey, Nebraska. The area is sand hills with grass and planted forest. I've never visited, but always been interested in it. From the photos I find online, it looks like some of the forest is pleasant.
http://monkeywrenchcycles.com/halsey-nf-overnight/
Some of the grass looks deep. And the sand might make running a chore. And the roar of motorcycles might not be so pleasant:
https://www.youtube.com/watch?v=rB3Z07Rhk_0