Just a guess, you might want to check around down my Caesar's Creek Lake/State Park...It's a pretty lake and if I remember correctly, it starts to get hilly around there...
From South Dayton: take Rt725 East to Rt42 South to 73 East...
or
Take Rt48 South to Rt73 East
Either way should be about a 20-30 min drive and definately be worth the drive to check it out.
If you enjoy the drags, check out Kil-Kare...1/2 way between Dayton & Xenia on Rt35. Really nice drag strip.