It's definitely easier with a large plot of land. Iowa is largely setup on a 1 mile by 1 mile grid of roads, making plots of 640 acres. I don't know if the grid of gravel roads is common or not.

I've heard of John Deere being able to stay within about an inch of the previously traveled path on subsequent passes through the field. "Guaranteeing" you won't drive over previously planted crops and being able to customize the spraying, doing most driving autonomously,and collect yield per acre in real-time during harvesting, etc. make it a compelling solution out here.