We lived for a few years just north of Detroit and visited Ann Arbor a time or two. We never visited Zingerman's, but it's very popular so I'd plan accordingly (especially on game day).

If there's time, try and local cider mill, too. Our favorite thing to do during our two falls in Michigan was to check out the cider mills. Get some *unpasteurized* apple cider and some apple cider donuts. Unpasteurized cider makes for the best apple juice/cider I've ever had. Not so good I'd drive hours to get it, but definitely worth a try if you're looking for a unique experience.