Roswell is 200 miles, and 3 hours, which includes the obligatory stop in Vaughn. With regard to Las Cruces, I've been there a gazillion times and agree with hungry unless, of course, there was something that I missed??? If you go as far as Roswell (yawn, except 4 UFO's) and you've never been to Carlsbad Caverns, that would certainly be something worth considering. Also worth considering is not the typical tourist tour, but the private tours to the 'newer findings' - tours which have to be arranged in advance.

Snoop the official website and maybe you can find some more info.