Since it's an afternoon game, fewer people will be doing the "dinner and shuttle" thing, so it's likely the surrounding parking lots will be filling up quicker. Last time I went I was on Huntmar, crossing over the 417, and I saw a few people stop and back into the road going off to the right to the car dealership area (now I get what NEELY was saying -- that's the "Autopark"). I was there about an hour before game start and there were still spots available. Another way to get to that road is go down Palladium, past the SBP, turn right into the Autopark, go around until you hit that roar (it goes off on the right, just after the GM parking lot, I think).
Come to think of it, I bought two cards from them, maybe I'll give my salesman a quick call next time and ask if I can park in their service area.