100% of LDS will vote for Mitt. That gives him a large advantage in the mountain west states.
Utah has a primary date of Feb 7th, 2012, which looks to be in violation of the GOP rules. I'm sure it's planned to give Romney or a boost. We'll have to see what happens before now and then, but I do wonder how much momentum it will give him, considering hat fact that he'd win in Utah even if he never showed up once to campaign.
http://www.politico.com/news/stories/0311/51044.html
According to this (footnote goes to the RNC) Wikipedia article, Nevada is slated for a February caucus. I wouldn't be surprised if (as you said) Romney won Nevada.
http://en.wikipedia.org/wiki/Republican_Party_(United_States)_presidential_primaries,_2012#Primary_and_caucus_dates
I don't expect him to win Colorado if anyone decent is running, though, because as I said up-thread, he didn't impress anyone here in 2008. Romney won here in 2008 because McCain ran a spectacularly lousy campaign and gave the finger to Colorado wherever and whenever he could. Toward the end of the campaign leading up to November, pictures in the media of McCain's campaign headquarters statewide showed that they were closing early, opening late, and half the time the people there didn't know if they were afoot or on horseback. Any warm body could have beaten McCain in 2008 here.
Besides, in the end, what can Romney do to change the outcome? He had 147 delegates (10%), and was blown out of the water by an underfunded, meandering, and late-entering Huckabee with 197 delegates (14%).