Madison's Farmer's Market is one of the best there is. First, it's set on our incredibly beautiful Capitol Square. Next, there are dozens of vendors. The food is fresh, cheap and bountiful. You will have to park off the square and walk up, but it's such a lovely area, you won't mind. Wander down to the Lake after the market and have a lovely day.
The Dane County Farmer's Market is one of the best in the Midwest. On certain weekends, there are events geared towards kids, so check the Web site - www.dcfm.org/ -. Great activity for adults with children they push in strollers. You can also visit the Capitol or the Madison Children's Museum the same day.
Downtown on the Square - It is a must do April through November.
Hundreds of stands with fruit, veggies, flowers, honey, baked goods with the Capitol as a background and lots of interesting people.
The lots of people can be a downside - manuvering with a stroller can be tough and you have to keep a hold of your childs hand.