Not the most direct route between the two cities [1]. It looks like there are at least two parts of the route that don't follow interstates. The excursion up to South Dakota to go past Mt. Rushmore makes sense, but I can't figure out the jog into New Mexico. Unless someone's really interested in a couple of National Monuments in that corner of NM, it looks like the only reason for that jog is to go to the Four Corners Monument with the minimum travel distance through an Indian reservation.