rowing/picnic recommendations - daytrip from Cincy

If the rain ever stops in this part of the world (really, it’s been like Blade Runner around here), I want spend a pleasant afternoon with my sweetie, on some quiet lake, rowing out to an island or beach for a picnic lunch. Ideally, this would be something within an hour or so of Cincinnati. I’ve found a few parks and such that look promising, but nothing that really jumped out at me. I’m leaning away from the “float trip” style thing where you show up at a certain time, go downriver, and then get a ride back with the canoe livery folks. I’m in reasonably good shape (I will be doing all the rowing), but I’m not looking for some endurance test, and I’d like to avoid the “extreme guys” from Harold and Kumar Go to White Castle. Just a nice afternoon with the missus. Anybody have any recommendations?