Ann Arbor is OK when but be careful of all the one way streets downtown. I lived there for 7 years and still never really got used to them.
Since you'll be so close to Dearborn, a trip to the Henry Ford Museum and Greenfield Village would be nice.
CLICKY.
And by the way, Brian, what are the Smoky Mountains like in April? Are things turning green and blooming that time of year or are things still pretty much brown and leafless? My wife will be down there the week after Easter.
Mike