Going through old threads and curious whether or not the OP has made any decisions on this?
I live about 30 miles NE of Cincy in a small town called Morrow. I'm about 10 minutes from Kings Island. I'm just about exactly between CVG and DAY (roughly 45 minute drive to either) and just over an hour from CMH. As others have said, DAY is *much* cheaper than CVG.
We moved to southern Ohio from the Detroit area (about an hour north of Detroit) and have been very happy here.