^^I live in the area so I thought I would chime in... I don't know much about that campground but the water is rocky in that area if my memory serves me correctly. However, if you don't mind driving to a spot that isn't rocky from that campground, there is a launch where the Nottawasaga river meets Georgian Bay and there are no rocks in that area...
The river is 6ft deep on average. Depending on the wind the waves can get pretty large in the bay. Usually some boat traffic but in the last couple years it hasn't been as busy as previous years.
There is a fee to park at the launch (I think it's about $13 a day)