Checking the Tesla map, if you select 2014 it shows adding another Supercharger between Superior and Missoula. There are not many stops along that stretch of I-90 with services. Could be Alberton (my bet), Hudson, Frenchtown or Wye. I admit to not understanding why another one is needed here, perhaps to better serve to 60kW cars, hopefully someone that knows that stretch can speculate on the need. Interestingly they are still showing Coeur d'Alene as coming soon...not much time before 2014 is over.