I'll chime in again regarding my kids' experiences.
My son got to go with his mom (I didn't get to go on that trip, work related) when he was 7.
My daughter was born when he was 13. We planned to take her to Disney World when she was 5. The plan was to road-trip it as soon as her pre-K year ended, which is what we did, along with family friends and their daughter, who was a year older than our daughter. Then an unexpected thing happened, where we were with my wife's family and I happened to mention that I would have our daughter send a postcard from Disney to her cousin, who was in 3rd grade at the time. By the time of this trip, our son was at A&M and wasn't interested in tagging along.
The cousin's family was not in any financial shape - nor would they ever be - to be able to take their daughter to Disney. I had an idea at that moment that required buy-in from my wife, the cousin's parents, and the cousin's school (she would not be done with her 3rd grade year before we were leaving). I also had to discuss with the family friends since we were all going to cram ourselves and our luggage into my wife's van. After everything, we surprised the cousin with an announcement that we were going to take her to Disney as well.
That trip went well, all things considered. No real meltdowns that I recall, but then, we had strollers and we routinely took breaks in the middle of the day to go back to the resort and swim or nap. And we didn't get crazy in terms of the number of days that we were at Disney World.
Two years later, I planned a surprise trip to Disney for the days leading up to Thanksgiving. That trip was just our family, along with the cousin. We weren't able to keep the surprise for the cousin - her mom let it slip out at some point, but thankfully, the cousin was able to keep her mouth shut any time she was with us. My wife pulled our daughter out of her 2nd grade class under the guise of a doctor's appointment, then when they came home to "pick up something mom had forgotten", she found the cousin and me waiting in the driveway. I had wanted to keep the surprise up until we disembarked from the plane in Orlando, and had even gotten so far into that story with the idea that the Aggies were playing in Florida and we were going (never mind that we left on a Tuesday, she wouldn't have been suspicious over that), but then someone in my party, I think my wife, let it slip that we were going to Disney. The look on my daughter's face was worth all the secretive conversations with the wife and cousin's family, all the time keeping that news hidden away, and all the planning I did to put that trip together. Of all the trips we took to Disney, this one was by far my favorite.
On this trip, I believe we were in the parks 6 days. I had booked several character meals, but on the plane when I asked the girls about those, they were more inclined to ditch those so they could spend more time on the rides. We also did the Christmas party one night, where we took advantage of short lines due to most people watching the parade and rode a bunch of rides a bunch of times. We were in the park that night until it closed, which was 2 am. Not a peep out of the girls, even the next morning - although I don't recall getting to the next day's park at opening.
Our last trip was again with our family friends and the cousin. The cousin was a senior in high school, my girl was in 8th grade. This was a 7-day trip at Thanksgiving, with character meals every day and all the big rides scheduled. The cousin posed for a lot of photos (either Photopass or my own camera) for her senior photos. My wife hosed me on the Millennium Falcon ride when one of the cast members said they had room for 2 more in one of the queues, right at the back, when had we stayed put in the main line, we were going to be first in line for the next available cockpit, meaning the pilot's seat. I was ticked, and have not let her live that down, and have told her that when we go again (and we will) that she will keep her mouth shut if that situation occurs again.
On that trip, the cousin pulled me aside and thanked me "for this". That was incredibly gratifying, to see her acknowledge what we had done for her. When I look back on that, I can't figure why we didn't consider taking her from the get-go given that she is such a big part of our family. But I'm glad that we were able to do that. These trips are not cheap, but for all these memories, I think the money was well spent.
I've asked my daughter what she remembers about each of those trips. She remembers the last one best, obviously, but she does remember the earlier trips pretty well also. Maybe not a lot of the details of that first trip, but she does have good memories from that one.
This may not be what a lot of families can or would want to do. It is a huge cost in terms of money and time to plan, and there are so many places that families can vacation to that don't come with those costs. And we've done several of those kind of trips as well.
We'll be going again pretty soon. Our son and his wife will soon be blessing us with a grandson. And about the time that kid is 4-5, I'll be 60, which I had already told my wife that I am taking myself to Disney for that particular birthday. Looks like it will be more of a family trip with the grandson (probably will take his parents as well, but will offer that as a break from the kid that they might actually want more than a trip to Disney).
