I used to go to Cedar Point 1-2x/year. I went a ton as a kid and remember absolutely loving it. There is a great variety of rides, plus some fun play areas for kids.
Re: Hocking Hills, my favorite hike is to Cedar Falls. There ARE cliffs in that area, but you have to seek them out a bit. Any of the caves are pretty fun also.
I second the Kelley's Island recommendation. It's WAY more family-friendly than Put in Bay, which is basically 50 year old women on girls' trips getting drunk or college kids getting drunk depending on the time of year. Kelley's Island is SO fun. You can rent a golf cart and ride around the entire island. There's a fun playground at the school, the glacial grooves, a winery (not incredible but not awful, and good food), plus some interesting walks you can do around quarries and lakes.
Other stuff that's awesome in Ohio cities: - Columbus: COSI, north market, zoo, Franklin Park Conservatory, Short North especially on gallery hop night, Slate Run (historic farm that is a BLAST for city kids--you can ask for chores, collect eggs from chickens, etc) - Cleveland: Little Italy, west side market - Cincinnati: Natural History Museum
And outside of Ohio cities: - Malabar Farm: great festivals, can visit animals and grounds. I went ALL THE TIME as a kid and loved it. PLUS Humphrey Bogart and Lauren Bacall got married here. #legit - Mohican State Park--Do the Lion's Falls trail. Perfect for kids. You can play in the water afterward too. - Roscoe Village--fun for kids. You can make candlesticks and such things. - Amish Country--NOODLES! PIE! Plus a bunch of country decor if you like such things.
There's a lot to do in that area. Sandusky has a lot of tourist attractions (Kalahari, great wolf, cedar point, etc), and put-in-bay or Kelly's island aren't too far away and are fun to visit for a day. Cuyahoga valley national park is about an hour and a half east and close to Cleveland. A lot to do in Cleveland too.
I know people from the Pittsburgh area who sometimes drive to Ohio just to go to this really good sandwich shop. I am not sure of the name of the shop, but apparently it is somewhere near Cleveland.
I haven't been there in 13 years or so, but Cedar Point is really fun. You could easily do 2 days there. I also really like Put-In-Bay and Kelly's island which are just a short ferry ride away.
I know people from the Pittsburgh area who sometimes drive to Ohio just to go to this really good sandwich shop. I am not sure of the name of the shop, but apparently it is somewhere near Cleveland.