Other Stuff to do near Sandusky????

I am taking my family to CP for 4 days on Resort with 3 days of park passes. June 10-14. Checking out on a Thursday. We were thinking about sticking around for an extra day if there is something else of interest in the area. We are from St. Louis, MO and driving. After 3 days of riding coasters I am not sure if I will be able to walk but would like to know of anything we should check out before we leave. A friend had mentioned Put-in-bay? Suggestions????

Thanks and looking forward to this trip for sure

The Lake Erie Shores and Islands website is a great resource for anyone visiting the area.