Dayton is inside an hour from Cincy, allow for an extra 15 minutes if you're leaving from CVG (or are you flying into Lunken?). Newport is nice, has a bunch of restauants in a mall on the river, plenty of bars there (Jefferson Hall is a good one, inside the mall next to the movie theater.)
If you go into downtown Cadillac Ranch and The Lodge Bar are the two best places to find tail, Cadillac is on 5th street and Lodge on 7th.
Don't go to the casino, SuperDud is there.