When Sucre gets the old man's car, and the car stops in the middle of the desert, in the close ups we see a big tree in the background behind Sucre, but in the more wide shots of the car and Sucre there is no big tree anywhere near, only some small bushes.
It is 829 miles from Helena, MT to Denver, CO and 770 miles from Great Fall, MT to Denver, CO. In this episode they state they have about 450 miles to get to Denver from a point between Helena and Great Falls. A little more research should be done by the writers sometimes.