Islandbayy -- You should use a LOT less energy driving at 55 rather than 65 -- at least that is true when temperatures are not so extremely cold. Since you are galavanting around the state for us, would be curious to see your experience with that if you want to try? In October I drove Madison to Minneapolis - drove 70mph on the way up and stopped at Jellystone to charge for 1.5 hours to make it. On the way home I set the cruise at 55 as soon as I was on the interstate and drove the 300 miles without stopping, still with ~30 "in the tank" when I got home. The drive took about 45 minutes longer at the lower speed, but since I didn't have the stop-to-charge time, it was net faster.
300 miles? You must have had a tailwind too. The thing that matters most is airspeed rather than groundspeed.