...survivors of the notorious Sand Creek massacre...
The massacre site is here:
38.543909, -102.505025 and could be along your route with not a serious detour south.
The national park service has done a nice job at preserving the area and it likely looks very much as it did that morning (nobody calls what happened a battle). The road to get there from Chivington, CO (the galling name of the nearest nearly empty town) is not paved, but it's not all that bad a road if things are dry. There's a small visitor center and the trails are well marked and the markers are also well done. It's wide open prairie just as it once was, and I can predict that you won't be bothered by crowds.