We did a long trip (11 hours) down the California coast. We did not go all the way into Anaheim though. What really surprised me was how much the swaying of the train affected me. When we got to our hotel I had to make a run to the store for Dramamine.
The seats were similar to riding in a nice bus, they reclined and there was a footrest. Not as crammed as an airplane seat. You would walk around as much as you wanted. Some cars had a room downtairs where kids could play. There were a few toys and a video player. There is a formal dining car that you have to make reservations for (the steward will come around shortly after you board to find out what seating you want) or there is a quick service snack bar that sold microwaveable stuff. It was all pretty exspensive. If at all possible, I'd say to pack a small cooler and bring as much as you can with you.