The travel would be considerably worse for them in football, but they could still play SDSU every year if they wanted to. Usually FBS teams don't travel to FCS teams though, but I sort of think that their fan base would demand to keep that rivalry going. With that said, if SDSU continues to be dominant, especially in the absence of NDSU, it probably wouldn't be long before the MWC picks them up too. The MWC is going to need quality football to stay relevant.They should step up. Better travel conditions than The Valley as well. They also have the fan base to support that move as well.
They'd remain in the Summit League for everything else, so I think it would be a good move for them. With the extra money they'll get from TV they'll have more than enough money to travel all over the western half of the US. That's one program where they've been so dominant that their fan base has gotten bored with it. Whether they'll admit it or not, no one wants to watch a bloodbath every Saturday.