It depends on your destination. Ohio and Michigan share a border, so it is theoretically possible to step across. A lot of people make the hour-long commute between Toledo and Detroit. Columbus to Lansing is about 4 and 1/2 hours and Cincinnati to Grand Rapids is about 6. The U.P. is considerably farther.
About 4½ hours by car.
5 and a half hours
Geneva, Ohio to Kalamazoo, Michigan is 4 h 32 min (306.1 mi) via I-90 W
It would take two to three days for mail to be delivered from Michigan to Ohio. That is unless you send it overnight mail, in that case it would be delivered the next day.
about 3-5 hours depends what route you take
not very long
It takes about 3 hours and 52 minutes.
It takes roughly 1 hour to 1.5 hours.
next day for priority mail 2-4 days first class
The shortest driving time is 4 hours and 43 minutes.
Google Maps estimates the driving time as 1 hour and 13 minutes.
Google Maps estimates the driving time as 2 hours and 47 minutes.