Hi I live in Cincinnati suburbs.
Your best bet is to stay in the Northern Kentucky area.
Downtown Cincinnati hotels are nice, expensive and offer off the street parking but there really isn't much to see or do downtown for a family. Singles and couples, that is another story (arts centers the Aronoff..etc..).
You don't have to stay right on the river front (Embassy Suites). You could go a little further south on 75 and stay in the Florence area. There would be more food options and cheaper hotels. The drive is extremely easy since both are only 5-10 minutes apart and right off the interstate.
The Aquarium and Newport on the leevee are really nice attractions. The Aquarium can be expensive though (I think it's around $16 or so for an adult- ask the hotel if there are any local discounts going on - Sometimes Local Kroger stores will have $3 off discount tickets).
Also, the Cincinnati Zoo (maybe 15 - 20 minutes away off of 71
north or 75 north) is a great place for families. It is the second largest Zoo in the US. I would rather go here any day than the aquarium. Take a picnic lunch and turn right just as you go through the admission gate (in your car) follow the road until it ends and park in this lot. There is a shaded picnic area with restrooms and playground here. You can also access the zoo from this area.
Cincinnati is not as bad as national media reports have made it sound. Most areas that do experience the violence you will not be around. You will recongize that you are heading in the wrong direction in those areas before you ever get to where it's bad.
Have fun on your trip!