I just got off the phone with the event coordinator for the park. She e-mailed me the rates, which, for what we want, would be $152 per hour and a $1,300 damage deposit. This applies to the Pavilion or the clock tower area. There is also a $60 "Special Event" permit that applies to events with over 100 people.
There's more...
Saturday, there's an event that has the park until 4pm, but she suspects that their clean-up time will be about 3-4 hours long. Sunday, there's an event until 9pm, and that's not including clean-up. Monday is all booked until 6pm.