Before traveling to your destination, check out local sites and find out when the farmer's market is in full swing. See if any of the vendors are close, and find out if you can take a tour. We've found that touring urban farms gives us some great ideas of things to try in our own gardens, especially because they often capitalize on growing a lot of fruits and vegetables in a relatively small space. You might even find a farm or co-op that offers tours.
While traveling, we like to get a feel for the place by walking around—especially more urban areas. We've always been surprised by the community gardens we walk by, showing how community gardening is alive and well all over. Not to mention, many cities have botanical gardens, full of native flora, near their art districts.
Do you have any plans to do some urban garden spotting while you travel?