Well the Super Grover is a platinum pass, and does get free parking at all Busch parks. Not sure where you don't think it does not include parking. I have had Super Grover passes several times, and have always had free parking at all the parks. If you're only going to do SW, then maybe a hotel/ticket package or just tickets (check the blue Friday prices) and pay the parking fee. Heck if the lowest priced SW AP, that includes free parking, is not much more than the days ticket you are interested in, check out the SW AP prices, again on blue Friday. When I do have to pay for parking, I always factor that into the rate I'm paying, either for a park or hotel.
I hope you have a great trip.