The second time we went, we surprised our kids. It was the BEST thing ever. Basically, they never figured it out and we had to tell them at dinner at O'Hana! My kids were 7, 5, 3, and 1 at the time
We told them they were going to see their cousins (who live in NJ) for Easter (this was not a lie -- the cousins were joining us on the second day!!). They were completely clueless the whole way.
We flew, so we let the flight attendants and our neighboring passengers in on the secret so no one blew it (direct flight to Orlando w/4 kids is pretty obvious where we're going!)
We thought they'd figure it out on the plane when they heard Orlando, but nope. Then, at the airport, it's pretty hard to miss that you're in WDW country, but again, nothing. Then at the rental car center, my oldest, who was 7 and could read very well, walked over to a Mickey statue and picked up a brochure to show me DisneyWorld, "for the next time we go." Then, all the way from the airport to WDW, there are about a jillion signs . . . no one caught on (and 2 of them could read!!).
The girls sat in the back of the minivan, just playing away. My 3 yo was the only one who even noticed the big arch as we drove on property. He said, "Look, a Mickey Mouse movie . . . can we go?" We said yes . . . no more questions.
Then, we had reservations at O'Hana first thing (we told them we were hungry, so we were going to dinner before we went to see their cousins). We drove to the Polynesian, and started walking in. Realizing that this looked weird for NJ, my 5 yo dd said, "Mom are we in Vermont?" (uhhhhh, no . . . not many palm trees in Vermont!!). We just said no. They were looking all around, but didn't figure it out.
Then, inside, the place was swamped (Easter week). Everyone had Mickey ears, shirts, bags, etc. Clueless . . . Finally, after we sat down in the waiting area, ordered drinks and appetizers, I asked my husband if we should tell them yet. We finally said, okay kids, guess where we are? They said, "New Jersey?" No, Disney World!!! They totally did not believe us. They were laughing and happy, but still cautious. Finally, when we got into the restaurant and had a beautiful view of the castle, they started to believe us . . . . It was so hilarious and sweet and innocent!! I wish I could pull it off again!!!!
We did a surprise on our last trip, but only as far as the airport for the older kids. The little one figured it out as we were leaving the rental car garage.
Have fun with it!! These are some of the most priceless memories!!!