Look at Myrtle Beach State Park if that area is close enough for you. Sites have water/electric and maybe some with full hookup. Not directly on the water but within walking distance of a lengthy beach. Best of all is DH will have a very nice pier for fishing (when we were there it was no charge for campers).
Closer - try Straits State Park at St. Ignace MI. Water will be chilly but lots of water views there. Also you can take the jet boats to Machinaw Island for a day of biking or horse riding. My children always loved going there.
