It might not be centrally located but, the Sandusky, Ohio area on lake Erie is really beautiful. there are campgrounds on Kelly's island and south Bass island
plus lots of Hotels & B&B's in the town of Put in Bay on South Bass island. (Put In Bay is kind of like a mini Myrtel beach) The islands area has plenty of sheltered bays in case of bad weather. There is a sea kayak club in cleveland that does weekend events in the area that may provide a good starting point for organization. They are doing their campout in September this year. Check out the schedule on the website. If you click on "kelly's island campout" they have pictures from last year including a couple hand made boats.