I found Super Express by accident, and it was a happy accident!
They used a very comfortable Chevy van for the transport, and even though it was full it was terrific.
Super Express operates in the real world, so you do have to account for traffic and things like delays caused by accidents in the Cajon Pass.
Super Express will drop you at any hotel between Mandalay Bay and the Strat, and will take you downtown or other places in Las Vegas for a substantial extra charge-which is LESS than a cab fare by far.
In Vegas, they pick up in the morning at Caesar's Palace.
Two things: First, if you don't want to watch the movies bring along ear plugs or your I-pod because the other passengers are going to watch the movie. Makes the time fly! Of course, so does sleeping!
Second: They stop only at Barstow Station. There are food joints inside (including McDonalds) but if you go about 1/3 of a block down Main you will find Tom's Burgers, which has a wider selection. I just had a shake from Tom's and it was pretty good.
I calculated my time: if I left my house and went to the airport, flew to Vegas and went to Caesar's, it would take me longer than if I went to Union Station and met Super Express.