I don’t want to embed this here because the pictures end up gigantic, but here’s a link to an infographic that caught my eye, for various reasons.
There’s not a whole lot of artistic value here, but the simplicity works. The way the lines are portrayed makes this look like a weather map (and/or a topographical map). It’s effective because the progression from 1800 and on is clear – from the lines being tightly bunched in the northeast in 1800, to travel finally moving west of the Mississippi in 1857, and finally to the 1930s railroad map, where the entire U.S. is reachable within three days.
Having spent lots of time in Western North Carolina, North Georgia and East Tennessee, the circle around the region in the 1830 picture intrigued me — it took two weeks to reach that area, when travelers on a different route could reach the Mississippi River in that same time frame.
Today, I don’t think there would be a single line on the map, save, maybe, for a few remote pockets (South/North Dakota, Montana?) — though I’d imagine you could reach those places in a single day.