Detroit coney island: Best time to visit Lafayette / American?
I've never seen them either packed or empty. They're so fast (i.e., instantaneous) that a crowd isn't really an issue. As to the parking, I'd probably go during the day when you can get a meter--probably you can find one on Griswold or Lafayette anytime except evening rush hour. Feed meter conscientiously. If you don't want to park on the street, there's a garage a block south on Griswold on the right. Michigan People Mover stop is not far, either, but it's currently closed for repairs.