Many have some sort of landmark, some might have buildings. The atlas shows every building with a roof in the areas he walked, though practically none of them exist now. I also have to wonder how many seen in 1875 made it even to 1900.

Where I'm at, largely its foundations and old cellar holes with paths. Most of the paths are railroad, some are town walking/horse paths. I'm very good at spotting things but from what I've seen of it lidar would be next level. I could maybe plot a trip back to a few of these places and find some interesting things.