There is a parking garage which is adjacent and east of Diddle Arena (BB). The first 3 floors are reserved for the foundation club members but there is parking open to the public on a first in bases on the other floors. I was told by the folks at WKU that parking can be tight. They've only sold about 10,000 tickets according to the person I spoke with but if they're like us there will be a last minute rush for tickets. Most posters on their boards are thinking sell out. The weather will be great for football. And with folks in town for the high school football championship I would think some would attend the game since they will already be there. Parking map posted below. Remember that USM will have a tent in the South Lawn (across the street and south of the stadium).
http://www.wku.edu/transportation/maps/2015_c_usa_championship_tailgating_map.pdf
http://www.wku.edu/transportation/maps/2015_c_usa_championship_tailgating_map.pdf