Secondary roads away from cities in Ohio are usually quiet, without much traffic outside of the commute hours.

I like the Strava Route Builder for riding in unfamiliar areas. (You need a free Strava login to use it.) It uses the Strava Heat Map, a year's worth of uploaded GPS ride recordings, to pick popular biking roads. It's way better than using Google's Bicycling option, which normally just picks a direct route that avoids multi-lane highways.

The Columbus Ohio area Heat Map link. Click "Toggle Labels" to show the road and town names. The URL changes as you pan or zoom, so you can bookmark that view.

When I just picked the two end points, it routed way east then north, to stay on very popular roads. But that seemed to be a long way out of the way. So I re-did it, viewing the heat map, and clicking on reasonable alternatives.

It didn't want to route on the Heart of Ohio bike path, even though it's showing as bright red, the most popular. I had to manually force it along the path. It appears part of the path isn't in it's database of roads. The path shows as dark green in Google Map's Bicycling option, which means it's paved. There's one short section in brown, probably a crushed rock surface.

Here's the route link. 67 miles, 2800 feet of elevation gain. Strava routes kind of assume you have a GPS to navigate, they often have a lot of turns.
(To compare, here's the route strava selected by just clicking the two end points. 75 miles, 4200 feet. Ohio gets hilly as you head east! It passes through a few small towns, so water and snack food are likely available.)


Here's a screen shot of the route, showing the heat map roads, as I finished drawing it. Each white dot on the route is where I clicked to make it take that road. (The Route Builder has the usual Undo-Redo buttons, and I can drag a route over to a different road, too.)