If you find you want a little more time around Sandusky, there are plenty of things to do besides Cedar Point. Which is quite fun, but we find we can cover that whole park in a day if we go on weekday rather than a weekend. There is a little drive through animal park called African Safari Park in Port Clinton, not far from CP. You drive your own car through and the animals will come right up (an often INTO) your car. The kids get a kick out of it. It doesn't take long to go through....but you can take as long as you want and drive through as many times as you want. A few miles away you can get the Miller Ferry to Put-In-Bay, a cute little resort island in Lake Erie. Once known only for it's bars......it's quite family friendly now. The main mode of transportation are golf carts. You can rent by the hour or the day. They have some nice parks along the lake, caves you can tour, mini-golf and other kid friendly stuff, as well as tons of shops and restaurants. You can easily spend a whole day up there.
regards