We went to Polar Express last Sunday. The simulator *is* the polar express. And yes, the animal exhibits are all open after the simulator. Only the narwal area is decorated; the rest is business as usual.
“The press [should be] a watchdog. Not an attack dog. Not a lapdog. A watchdog. Now, a watchdog can't be right all the time. He doesn't bark only when he sees or smells something that's dangerous. A good watchdog barks at things that are suspicious.” – Dan Rather
I did the simulator portion of Polar Express last year, and if its the same thing this year, its pretty terrible. They don't bother creating any new footage for the ride. It's just scenes they pulled from the film including parts where you can see the train from the outside when you're supposed to be riding it. They made no effort to make you feel like you're in the movie itself, its more like you're in the train watching the Polar Express movie on a screen while it jossels you back and forth. Overall its pretty nauseating and I don't get nauseated on rides very often. Everything outside the simulator looks spectacular though, the theming is awesome. But If I were you I'd skip the ride and just rent the movie. Just shake your head violently while you watch it if you want the same experience.