I would recommend Huntington Beach State Park. A little further south but still an easy drive to any of the attractions in MB. It has the best beach in the area. Decades ago they built a jetty to control beach erosion in MB. Didn't work. All the sand they dump on MB beaches finds its way to Huntington Beach, so the beach is getting bigger.
I like MB State Park, but it is MUCH busier. It is also on the flight path for the airport. So around 6AM the jets starting coming and going. They are either landing or taking off right over the park and quite low at that point.
However, it is late to schedule anything this year. I was looking last week at all the coastal parks for sites in 2020, and the pickings are already slim for next year.