Indeed. Also the Ohio River was another trade superhighway, with short portages to Lake Erie and the rivers that fed into the Atlantic.
I’m convinced that Europeans arrived here during the American “Dark Ages”—the occupation of barbarian tribes after the fall of a great civilization or complex of civilizations. Cahokia was its Rome, and its lingering vestiges were seen by De Soto and others in the historical Mississippian populations in the Southeast.
The Lenape had legends of a great civilization to the West, the Alligewi, who they and the Iroquois teamed up to destroy.
That would fit a pattern. I wonder if human history and civilizations go back much farther than what we’ve found so far?