Realistically, I think anything over 5K and you would have to be really excited.
My ideas....
Pregame:
1) Have a tailgating cook off contest. Do a prize for meat and side. Have a local business sponsor it, and the winner gets his tailgating spot for free plus a tailgating prize package and some cash. Also, 4 trips to any road game he chooses.
2) Make the game free but simply accept donations at the door to the RCAF.