There are a couple of obvious quick fixes to this situation that can salvage at least some of the gameday atmosphere:
1. Make Thursday an early release day (at noon) for all non-essential University staff. Officially close the University at 4:00 p.m., including night classes. Provide staff who have to stay the afternoon an extra half-day of PTO to use at their discretion. Allow the night classes to be made up on the "bad weather" or "dead week" days, if you have such a thing.
This will no doubt upset some faculty, who will see this as the University putting athletics ahead of academics. However, being the U of M, you don't really have to worry about these claims too seriously. Everyone knows you as a respected research university with a strong dedication to academics. As a concession, use a few timeouts or halftimes during the season to run features on academics, award top faculty and staff, or to market to prospective students. Let athletics be a marketing tool and showcase for academics.
2. Immediately release a pregame traffic plan on all available communication channels, including in an e-mail to all faculty, staff, and students, and in a postcard to all football parking permit holders. Create and erect large plywood signs or use the lighted portable road signs in strategic locations the week before the game to inform campus drivers of lane closures and reversals. Make two good exits from each bank of campus that are all lanes in one direction, with no right or left turns until you enter the highway. Sure, some people may have to double back around, but it's better than everyone sitting in a traffic jam.
Have all other major roads be inbound traffic, and close University to through traffic. If you want to park in lots on the west side of the stadium, you come down University from 35, and for the eastern lots, you come down University from 94/280.
3. On Thursday morning, offer incentive to faculty, staff, and students who normally park in the lots immediately adjacent to TCF Bank Stadium to park in another lot/ramp (space permitting). That way, those who have to work until 4 or 5 will be out of the way of football traffic. Find a local business or two to help sponsor this. At the entrance to the stadium lots, have a sign and even a traffic officer who lets them know they *can* park there, but if they go park in X lot/ramp today, they can park there for free and get a free breakfast. Have a station set up at each alternate lot with free coffee and donuts from a local grocery store or bakery for everyone who parked there. College staff and students will walk a little bit out of their way for some free food.
4. Since people will not have sufficient time to set up their own tailgates (three hours, WTF, we have at least 24), rent the largest damn party tent in the Twin Cities and set it up outside McNamara or Mariucci, or preferably both. Again, find a local grocery store (or, hell, Target) to sponsor the World's Largest Gopher Tailgate! Charge five bucks a head (three for kids), and let everyone grab a hot dog or two, a bag of chips, and a coke. Set out some bales of hay around the perimeter for folks to sit on. Make one tent "family friendly" and have Goldy drop by. Let alcohol be permitted at the other tent, and have your local brewery send out some girls in short shorts and tube tops to walk around.
You can even ask some student organizations or Greek life to sponsor some games. Let them bring out cornhole or ladder golf or whatever it is y'all play at tailgates. Find some two bit local band to set up somewhere and play a few songs for free just to get their name out there.
You won't break even, but that's what your sponsor is for. I could see this turning into a big annual event where the WLGT is held the first home game of every season. With more time to plan, you can create more of a fair-like experience to compete with the fair and get people excited for the season.
5. By the end of the week, contract with a charter bus operator and publicize a park and ride service from a couple nearby malls or large shopping centers. Let folks pay 3 bucks a head to ride there and back, and let the busses get as close to the stadium as possible for drop off. The centers will have excess parking on a Thursday evening, and may enjoy busloads of hungry people being dropped off near their restaurants after the game. For many people, the low hassle of park and ride is a huge bonus, because they don't have to deal with postgame traffic.
6. Take every extra campus bus you can muster out to the State Fair and offer $20 family seating packs to fill every empty seat you have. Send a couple of pom squad girls out to help sell the tickets. If you've got to compete with the fair head-to-head, you have to go out there with the best advantage you've got. Hit people up in the parking lot before they pay to enter the fair - they can always go to the fair on the weekend, but the Gopher ticket deal only happens once.