Yep, ask a local. I would add that since you will be there in August, Lake water level may drop. Make sure on arrival you check with the locals at Nugent's. I'd get Fishahalic Charters phone number (if he'll give it) and call him when you get there. Get the latest on any obstructions or changes in Navigation. Also, the RR bridge will lower for trains (duh) so factor that 15-20 minute delay into your time schedule. There is a warning (I think a loud whistle?) when the bridge is closing, which is a few minutes before the train arrives. There is a sign at the bridge about this.

I think people at Cedar Point Marina get to enter the Park before the regular folks, or don't have to wait in the long line. Make sure you get your dock reservation now (I assume you already have) and find out all the details about the park.

Have fun!