If you want a more quiet, non-smoking property, check out the Vdara hotel. It's a little farther from the stadium (would be a 2 mi walk according to the googles), but it's not a casino, and the entire hotel is non-smoking. It's between the Bellagio and Aria, so it's a pretty good location.
My wife and I stayed there when we went to see George Strait, and it was very nice to be in a much more quiet and non-smoking property at the end of the night.