"There is some great dispersed camping around the whole area, and the farther from the main areas you go the better it gets. The pit toilets are near areas you can get large trucks / trailers / RVs to so the ATV crowd uses them alot, especially on the weekends. They tend to be loud and lit up at night, and in my experience the pit toilets are gross. If you keep going north by the creek or just away from the established sites it gets quieter. State Forest State Park is nearby and has great camping too.
What day do you think you'll be spending more time at the dunes? I am not sure if I'll be able to camp yet or not, might just head up early AM for a day trip."
I planned to go when the majority of the group would be there. Planning to camp with my older daughter Saturday night based on Saturday afternoon meetup time.