Ran from Alexandria VA to Cassopolis MI (Just a little North of Elkhart IN) on Interstates270/70/76/80/90 running speed limit plus 12 MPH (so that was either 77 or 82 MPH). Averaged 13.9 MPG. On the home I took I80/69, then US 30, I75/70/79/68/70/270. Ran 66MPH and got 17.4MPG. Significant...