What "big city" are you referring to? You really in Raton? I know that's a pretty good jaunt from Denver.
If the "big city" is Albuquerque, it's exactly three and a half (3 1/2) hours from Raton driving the speed limit - 75. Of course damn few NM drivers really observe the posted speed limit on I 25... I make that drive between two and four times monthly.