Speaking specifically of Nebraska fans, other than attending an Orange Bowl game when they were playing for a national title (where you'd expect them to travel well) I don't have any firsthand experience with them. But I have heard that they are among the most devoted in the sport, including when it comes to traveling....so I think you might be underestimating them just a bit. And you mentioned Washington, DC and the fact that it draws people from all over the country to live and work. But another thing it does is draw tourists, and so I think that will always be a draw for fans in Big Ten country to want to travel to UM games. And for the schools with the larger fan bases, you aren't always counting on the same people to come each time their school plays at MD.
As for Terps fans, yeah, if they aren't winning, then the novelty will wear off. But I still think that the athletic department could give variable pricing a try in 2014 (with OSU and WVU being prime games at Byrd). And like you said, there should also be lower prices than now for the FCS snoozers....although I would think it is already easy to get single-game tickets to those games for less than face value. Didn't they have a Groupon promo for an FCS game recently?
IIRC during their last years playing Colorado (over a holiday weekend) in Boulder, they were returning their ticket allotment, which is a lot closer than driving or flying half-way across the country. So no I don't think I'm underestimating them. They're a great fanbase, I just don't expect them single-handedly sellout Byrd on their name alone.
I do expect Ohio State and Michigan to draw well, regardless sort of like Florida State did (probably better ). And yes, you aren't depending on the same people with the large fanbases, but I think there's going to be much more people interested at the beginning. After that, if they have the choice between going to Maryland or other road games, I'm guessing they choose the latter assuming Maryland stays the status quo. The earlier in the year, the more likely they'll draw better attendance from these schools.
They had groupons for a few games, I think W&M + UConn, maybe some others.