Not sure where in Maine you're leaving from, but from the Augusta area. This is a pretty good route with lots of scenery, at least till you get to Buffalo.
Route on Google map
This will take you past Mt Washington, across Vermont and Adirondack Park in New York. An option in Burlington is the ferry to Port Kent rather than the road across Grand Isle. When in the mountains be prepared for snow, yes we ran into it last year in June in Lake Placid! In Alexandria bay take the Thousand Island cruise, a good trip. From there to Cleveland you can follow the lake or take the interstate, not too much difference. You will go by Niagara Falls and a trip across to Canada is worthwhile. I routed you to Columbus cause that is just about the middle of Ohio.
Hope this helps, use the Google search feature to find interesting stops. If you're coming back in June you might plan a stop in Lake George for
Americade
Ride safe and have fun