9 feet for one lane road between 10,000 cabins in a line 209 feet apart leads to 431 acres of road area. i.e. your less dense population already destroys more road area than the denser city did. It is an unfortunate reality that dense cities are orders more efficient for a modern society than spread out ones.

Phrased differently, if we have to bulldoze anyway, we should bulldoze the minimal surface area.

Let me know if messed up the calculation, I never used acres or feet.