While on vacation over Memorial Day weekend, I got a chance to see the farmer's market in Madison, Wisconsin. I didn't get there until most vendors were packing up, so I didn't get the full experience, but I did get an idea about this market. It's in a beautiful area, surrounding the capital building in downtown Madison. You walk around the entire building, stopping at vendors all along the square. One of the rules of this market is that there is no re-sale allowed. Everything much be grown or made by the vendor, so you know you are buying directly from the source. It is said to be the largest producer only farmer's market in the country and with all the space they have around the capitol I believe it.
The market is in a wide open area so it's seems easy to walk around, but again I wasn't there during the peak hours. As for parking we were able to find meter parking that was within a block of the market. There are also parking garages that are not too far away. I would definitely shop this market, biggest reason being the sheer number of vendors.
For more information on the market including calendar and hours, visit: http://www.dcfm.org/wandw.asp