First off, a great trip report, thanks for sharing. It sounds like United did an excellent and professional job in a trying situation. And don't forget the "ground crew" at CDC who definitely weren't expecting a "baby bus Jumbo Jet"!
A little off-topic, but when I first read your topic, I thought you got food poisoning on a flight from ORD to LAX (with a stop at the Centers for Disease Control on the way).
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by RichG:
Bet you wish you'd been on a DC-9 (built-in rear stairs)! Of course, that may be the only reason.
Interesting also to wonder about how United is going to fix the A319 in Cedar City and fly it out of there. Guess they're going to have to fly in mechanics and equipment, maybe in an RJ with built-in stairs? 
Can't see them flying it to LAS with one engine, even w/o pax.</font>
I seem to recall not too far back that a TWA MD-80 landed at the wrong airport, who could not accomodate the size of the jet, so it skidded off the too-short runway and into mud or something. Everyone was safe, etc, etc, but once the mechanics came to repair the aircraft, they didn't know how they would get it out of there (even with little weight and little fuel to get to a nearby airport). I don't know how it was resolved.