Here are some additional hiking/bike resources:

http://www.americantrails.org/resour...s/OHstate.html

http://www.trails.com/activity.aspx?area=10251

Also (this being FlyerTalk): if military aviation/airplanes are of any interest, the US Air Force Museum is located east of Dayton - from the Hyatt Place north of Cincinnati, it would be about 40 miles (IIRC) - lots of exhibits, and except for the IMAX presentations, admission and parking are free of charge:

http://www.nationalmuseum.af.mil/

(List of all planes at the Museum, opens as a .pdf file):

http://www.nationalmuseum.af.mil/sha...061222-016.pdf