Okay, so you know there can be ups and downs for a trip, right? It seems that we hear about so many people who get all hyped up for the 'perfect, magical' vacation, and the expectations get set so high that they can't be reached. It would be awful if the kids were all revved and then didn't have that great of a time, wouldn't it? If they got all excited about something, and it didn't happen that way?
So instead of - "What can I do to get them pumped for the trip? First time for all of them. What can I send them in the mail, etc.? I want their first time to be magical!!!", how about "How can I figure out what is important for them, what should I plan for with young kids, are there any issues with the kids" etc? Of course we all hope the trip will be great, but it just seems that sometimes the trip gets out of control before it even starts, the expectations get out of this world, and then the trip is a huge (expensive) letdown. It's happened to us once, and we learned to tone it all down.
Some things that are in your control to have fun with - matching shirts, finding out which characters are favorites and knowing if/when they can be seen in the parks (but don't let the kids know), maybe some small treats to have in the room? Window decorations used to be a huge thing to bring down, not sure if people do that anymore? The Mousekeepers used to do fun stuff with the stuffed animals when my kids were little, but you can't even count on that anymore, KWIM? I think letting the kids have access to the park maps before he trip might give them a good sense of what to expect, but sometimes the hype backfires.