Right now seems to be the best time of the year to visit the park actually.
Schools starting back up, so a lot of the kids are gone; the weather just might cool down a few degrees for you, but not enough to make a good water ride not worthwhile, and due to the fact that no festivals are going on, the park shouldn't be too crowded. A guy I know went last week and he said the crowds were fantastic: 5 min. waits on everything, even PK.
I think after this visit you'll find it hard not to come back again next year, or even for the big Christmas festival.
Bring in the label of any 20oz Coke product, and you'll get $5 off your admission for a one-day admission. That's the only deal I know of currently, but your hotel may have something as well.
