If one is an avid bike commuter, then 10 miles by bike (nothing but the legs powering it) is just a hop skip and a jump.
20 miles is tough, but well within reason (even for a leg of a round trip commute).
From Ann Arbor, you should be able to get out of the country in a half a day's ride (50 miles to Windsor, Canada), of course depending on finding safe bike routes.
From Ann Arbor, to Toledo is also about 50 miles to get out of state. Still a good half day's ride.
A little more ambitious to get to other states.
But, if you had a bike-car regulated at 20 MPH.... then it would be a long drive to get 100 or 200 miles down the road.
Those of us that have done long distance bike commuting know that a 100 mile freeway drive could be a 150+ mile ride using various low traffic secondary roads (which you may choose for a bike-car).
Of course the other issue with a bike is that we're rapidly approaching fall. So, those in the northern climate may find winter riding more challenging.