I tell people this all the time. People simply don't do ridiculously long drives but perhaps once or twice in their lives. It's very rare for people to drive this much....and yet, everyone *thinks* they drive this much. Which is why the superchargers are important. They're there, so people can see that it's possible, but they don't need to have massive coverage because nobody's going to use them.
Here is the data I use to support that:
http://research.microsoft.com/en-us...lications 2012/2012-01-0489 SAE published.pdf Note on page 2, a negligible number of cars are driven more than 150 or so miles a day. The range of single charge on a Model S is literally enough for 99.99+% of cars in America on a given day.
By the way, I have actually driven coast-to-coast via the Dakotas. South Dakota, anyway. Which for the Eastern 80% of the state is mostly barren except for a rather silly roadside in-joke which dominates the entire state, and the Western 20% of the state is one of the most densely interesting places in the country. The Black Hills are absolutely incredible, and completely full of cool stuff to do and see.
But I did that drive twice - once one way, once the other. And I probably won't do it again, unless I end up bringing kids along some time in the future.