I've been going to the Casino Queen weekly for the last 15 years. I love playing the slots. I'm considered VIP there. They have weekly give-aways and usually every month a car.
Didn't use any amenities but we were pleases with our overnight stay. It's pretty much a parking lot but we felt safe and the hookups worked well. Very close to the Arch. There was some train noise but that's expected considering your camping in a large city. We would definetly stay again.