51/49 Romney
Romney takes the swing counties, Arapahoe and Jefferson. Obama takes Larimer county.
Seems entirely reasonable. Though I'm curious why you think Arapahoe would flip before Larimer in a 51-49-ish Romney statewide win? That'd require Romney to improve on McCain's vote in Arapahoe at least 2 points more (from a 13 point deficit in 2008) than he improves in Larimer. You know a lot more about CO politics than I and your map is decidedly non-hackish, so I'm genuinely interested in your take on it.
Arapahoe would flip before Larimer due to it being mostly suburban and having Buckley AFB, which leads to a higher turnout of the GOP cause of military. SE Aurora has new booming subdivisions which would benefit GOP. Larimer county on the other hand has CSU, and it's culturally similar to Boulder county. I'm not sure about Broomfield county, it could flip either way since it's close to Boulder, but it's not important enough to be of concern. Adams county (where I live), it's mostly working class and has a higher Hispanic population, that's a lean Democrat county and hasn't voted for GOP since 1984. Jefferson county has the southern part (Littleton, Ken Caryl, Lakewood) which are usually GOP, and the north part of Jeffco is left leaning.
Think of it this way, the closer to the mountains the more liberal, the farther out, more GOP. This is when you exclude Denver county.
