Kings island is crowded in August. Hopefully your going on a weekday. Don't miss out on Your night ride on The Beast. It's worth the wait. Diamondback ask a ride-op for row 16 once you get to the top of the stairs to the station. Delirium has been shut down for almost a month now. If you have any other questions I'm your guy to ask [:D]
As for Holiday world I would suggest going for two days. I loved the park, there's no way to do everything in one day. If you like waterparks definently go for two days. Raven is in one train opertaion until Timberliners are on for operation to the General public. If your going late August you don't have much to worry about that. I always heard do Raven, Legend, Then Voyage. I would suggest doing that. Back seat on Raven is a good choice[:)] Pilgrums plunge isn't really worth the wait. I thought it was dumb to be honest. The lift is more interesting then the drop. Gobbler getaway is a good place to cool off and it smells like pumpkin pie inside.
Information about Kings island:
http://www.visitkingsisland.com/
Information on Holiday world:
http://www.holidayworld.com/
You could also ask questions to the park on there Facebook here:
http://www.facebook.com/HolidayWorld