We visited Kaifeng because we only had a couple of days and it was close to where I was working, but it was a great visit. There is a wonderful night market near the Soluxe Hotel with many vendors of noodles, dumplings, and other foods. We recommend the Da Jin Tai Hotel which is across the street for a decent, well-valued room. We also met a wonderful tour guide, Jason, that was very knowledgable and well-priced. He can do individual tours in his rickshaw or large groups. He speaks very good English. He is famous in the city and I am sure that any hotel (or maybe even person on the street) will be able to point you towards him. You might even see him around the city on his rickshaw.
But our visit to the city was very interesting and there were many wonderful flavors we experienced. Highly recommended.