NDSU is really a geographical outlier. Much better fit in the MAC, and much more likely to get an invite from that type of conference. I don't see many FCS teams moving straight into a conference like the MWC, to be honest.
In terms of Montana and MSU, with the WAC dead and gone, the likelihood of any FCS teams on the west coast "moving up" at this point are fairly slim. You need that intermediary kind of conference that the WAC was to pay your dues in before you're going to get into the MWC. Another alternative might be the Sun Belt if a team is dead set on moving up, but the travel in that league would be a nightmare (see Idaho). The other alternative might be to play independent for a few years, but that most likely results in a lot of money games to make ends meet, few home games, and decreased fan interest.
The upper echelon of the Big Sky has very slim options in terms of going FBS, NDSU probably has more options with the MAC.
Really, I think the best thing we can hope for right now is some sort of restructure between the lower end FBS conferences and the power FCS conferences. Who is more alike, Idaho and Florida, or Idaho and Montana? Kind of a no-brainer. I just hope that if an when it happens, we'll be in a position facilities-wise to land in that second Tier.