The American Solar Challenge is on again in July/August this year. In honour of the Santa Fe Trail Bicentennial, it will be following the Santa Fe Trail. The currently expected route is shown on the map above (although this still includes some guesswork from Google Directions).
The route crosses the 7,840 ft (2,390 m) Raton Pass. Starting from Trinidad, CO, the Raton Pass climbs 558 m in 22 km (2.5%), with a maximum grade of 6% on the steepest sections:
“Breaking camp while it was still early, our cavalcade began the steep and tortuous ascent of the Raton Pass. Today we glide easily over hairpin curves that in 1860 meant broken axles and crippled horses. The trail was a faint wheel mark winding in and out over fallen trees and huge boulders.” (Marion Sloan Russell, Land of Enchantment)
See also my previous posts about the history of the trail, my updated teams list for the event, and the National Park Service page for the event.
Because the exact route has not been released yet, very approximate elevations, based on Google Directions, are shown in the chart below. On the loop between Las Vegas and Santa Fe, the route probably goes over the Glorieta Pass, but that seems to be relatively gentle.