Planning a trip

Planning a trip overseas. I live between cmh and dtw. It is around 30% cheaper to have a flight start at cmh but connects to dtw. Is it possible to book the cheaper cmh route but skip cmh and board in dtw? The later departure time in dtw makes it easier to get to the airport and what not.

Also is comfort+ worth it over main? main at the moment doesn't seem nearly as crowded as comfort+

Thank you