The more I analyze this, the more and more I think that Billings is going to be awarded the tournament.
If the point of this exercise is to contain costs, then avoiding airports for team travel is the #1 way to do that I think. I count 8 teams that would likely bus to Billings. I could be wrong but I think that includes Weber who is probably right on the line as to whether they would fly or bus that distance of 525 miles.
If they do fly, Billings has direct flights not only to SLC, but also to Portland. I'm not sure if althletic departments are able to use an airline like Allegiant very often, but if they can Billings has service to both Vegas and Phoenix which SUU and NAU could both theoretically utilize if they were creative.
I am going to guess that attendance would be similar to what it has been in Missoula in recent years ranging between 4,000-7,000 for any game that either UM or MSU participated in. If the Griz and Cats met during the tournament, there would be the potential for 10,000+ at that game.
Lastly, if the presidents are set on making this change, I think Fullerton is going to push for Billings. He is on record as preferring to keep the current format, but as native of Montana, former MSU A.D., my gut tells me he'll probably think it is better off in Cat-Griz land if it has to change.