Tip #1- KEEP THE SECRET!
Do your best to keep the trip an absolute secret. They'll never suspect it, and that's the best!
Tip #2- BUILD SUSPENSE!
Come up with a fun scavenger hunt, leading up to the big reveal... drag it out as much as you can (within reason) to build up the suspense!
Tip #3- DON'T TRICK THEM!
From the videos I have watched, it seems most confusing to the children who the parents have tricked into thinking they are going somewhere they are really not, and then the parents surprise them with the truth. These children were way too confused to be totally excited!
Tip #4- BLURT IT OUT!
As clever as it may seem, don't have the kids have to "figure out what this puzzle means" for the reveal. It's confusing to them, and so their reaction will be to first question if you are serious, trying to understand what this all really means, etc. When it is time for the big reveal, just blurt out the surprise with as much excitement as you can!!! This is the best way to truly excite your children!! (or, it was for mine anyway)
Here you can see the difference in us Surprising the kids in a non-exciting way vs. how we surprised them with the above tips and how VAST difference in their reactions!!!
TOTALLY AWESOME REACTION!: