See that 286 Number? That's the actual energy you're using in the car to go one mile. The car has ~74,000 Wh of energy, so 74,000/286 = 258 miles of range on a full battery.
If you get that 286 number down to 240 where the EPA pins it (speed and acceleration are the biggest factors here) and you will get 74,000/240 = 308 miles of range on a full charge.
But why do that to yourself? Just enjoy the car and just plug the car in when you're not driving it. Florida has a million superchargers if you need to juice up in a pinch.