I went at a similar time last year and it was pretty packed in PA - consider fast tracks! (at least for one of your days)
Yeah, I was thinking this. In May the park was very quiet but on the weekend it was totally unbelievable. Since then I know of Two familys who have come back (One in June and one in July and from what they said it sounds like it was just as bad but for the whole week.
If its really busy then I'd head straight for Condor at the back of the park and work anti - clockwise. Don't be fooled by the FB queue, theres a massive cattle pen at the top of the hill so if the queue is coming out of the building and winding down the hill then i'd leave well alone until later. :)
The waterpark has a maximum capacity of around 5000 so it might be an idea to get in early and go to the park later as it cools down a bit.