Am I the only one who has been to KC? I lived there all my life until 1 year ago. The best place to go is the Plaza. It has all the shopping, restaurants and nightlife. All Spanish architecture with beautiful fountains and built along a river walk. Lots of fun outdoor cafes. Its about 5 miles south of downtown. Downtown at night is a bummer. I hope you aren't staying downtown. The Crown Center area is ok but not great, thats where the Westin and I think Hyatt hotels are. They are just outside downtown. There are some areas of art galleries downtown in a few square blocks (the "freight house district") but that area is just developing and if you are on the wrong block you are in a high crime area so I would only go to the gallery district with someone who knows it. Its worth going to the Plaza. Take a cab or whatever. Sometimes they have trolleys running from Crown Center to the Plaza. The weather should be cool, about 60 day and 40 at night, but fairly pleasant unless its raining. There are some casinos around if you like that but nothing notable. Its not exactly the most fun city in the world IMHO.
Beth