One week out of four, I have to come in to work at 6:30am on the Wednesday; the good part of this is that I get off for the day at 3. I was toying with the idea of hitting a farmer's market, and trying to decide between City Hall Plaza and Dewey Square. I'm looking for a couple of tomatoes - that's easy anyplace; other than that I'm mostly just browsing. A bonus would be one of the Asian farms like the Hmong stand at the Thursday market in Brookline. Any advice?