E.O.
That sounds like a lot of fun- and way more affordable than flying. I traveled Amtrak about twice a week last summer between Joliet and St. Louis. My only qualms with taking a longer trip by train is that you should probably expect it to be quite a bit longer than listed. The listed time to St. Louis is about 5 hours, and there were times that I was on the train for close to eight hours. You would still have a great time on the train, I just wouldn't schedule anything for right as you get to Vegas! Have a good time!