Take I-25 SOUTH, from Fort Collins, to I-40 WEST to GALLUP at EXIT 226B in Albuquerque, via E-470 EAST (tollway) to bypass Denver (EXIT 228 off I-25 to get onto E-470 EAST [tollway] ; EXIT 1A off E-470 [tollway] to continue on I-25 SOUTH to Colorado Springs).
Take I-40 WEST to I-17 SOUTH to PHOENIX at EXIT 195 in Flagstaff, Arizona.