Every time we visit Philly, we always make sure to take the train in to Chinatown one day for lunch. The kids love walking around, and you won't get better Chinese food anywhere. It can sometimes be a little dirty, and be careful of open vents on the sidewalk, but it's well worth the trip. My kids love seeing the live crabs in baskets for sale, and looking through the trinkets at the little shops.
Start at the Chinese Arch (there is so much detail - the kids loved pointing out letters and designs) and take a stroll through a reasonable-sized Chinatown that is right in the heart of the city. Stop in a few novelty shops (they are packed with brightly-colored, kid-friendly items) and pick up a souvenier for cheap. There are so many restaurants, so pick an authentic one and dig in - dim sum was very popular with our girls.
Go 1 block east of the Reading Terminal, and you’re in the heart of Philadelphia’s Chinatown. Stop here for authentic Chinese cuisine and products.