At the southeastern edge of the Piedmont is the (water)fall line, where rivers drop to the coastal plain. Towns grew at the fall line because cargo on boats had to be portaged around the waterfalls which also served as an important early source of water power. Mills built to harness this resource encouraged the growth of many towns. The larger rivers were navigable up to the fall line, providing a trade route for these mill towns.
As roads developed in America settlers were attracted to nearby communities because the roads provided access to markets. They could sell their products at distant markets, and buy products made far away. If an ancestor settled near a road, you may be able to trace back to a place of origin on a connecting highway.
No lists of settlers who used the King's Highway are known to exist.