Not real sure where you will be coming from but Harlan is always a must if you have never been. 10,000 acres of mild to wild. It isn't really close to the arc but may be on the way(slightly) depending on where you are coming from. There is also the Red River George area. Some really scenic riding in that area. However, you really need tags and insurance to ride that area due to most of it is county roads. There are a few challenging trails and great scenery. You could also look into Rush offroad park and Dirt Nasty. I don't really know of anything really close to the cinci area. There maybe something in that area that I am not aware of and maybe someone can chime in with more info.