It can get pretty cold.
However, my suggestion would be to bypass 8200ft Emery pass and instead go from Silver City to Deming on US 180 and then follow I-10 between Deming and Las Cruces. I did that route in 2001 and there were frontage roads for all but ~12 miles of the I-10 stretch. Journal page for that day:
http://www.mvermeulen.com/oneyear/Jo...11.htm#March20
Although I'm sure I'd miss the view from way up there, I'm definitely interested in this route. Could you send me some more information on the maps section of my site:
bikingforobama.com/maps/