I think if i told my son "hey you are going to disney with grandma and grandpa for a week" he would have the suitcase packed, the disney trip stuff found (pins, light up toys) and asking to swing by the dollar store for glow sticks. He is 5. Lol. Every kid is different though.
True! We took our then 3 1/2 y/o grandson for his first ever WDW Feb 2011 (his mom is not a Disney fan, but says I can take the grandsons anytime

). When I called her, all she said was fine, when do you want him, what all does he need, and are you sure you don't want to take the baby too.

I told her we wanted some one on one bonding time and would take the baby by himself when he turned three. We weren't going to be leaving for another 3 months, so assumed they'd wait until just before we left to tell him. Nope! That same evening he threw a fit for them to call me, told me he was going to see "Mick Mouse", and why couldn't we leave right now.

We spent three months with this kid wanting to know every day if we were leaving the next day to see "Mick Mouse". My son kept saying he was driving them crazy. They drove us to the airport and he was so excited, we had to make him hug them bye. I had told them that we'd would be calling them every morning and every night so he could talk with them. He had such a great time that he didn't even miss them. In fact, it was funny. At night and in the mornings, I'd call my D-I-L and hand my grandson the phone. He'd say a quick 'hi, gotta go, I'm busy, I'm having lots of fun, yeah, I love you too, no I don't wanna talk, bye, then toss me the phone. As I picked the phone up, I'd hear my D-I-L's sad voice, saying "I love you Levi, don't you miss mommy" and have to tell her he'd already tossed me the phone. After about the third or fourth day, she was laughing, but at the same time was almost in tears, saying "He doesn't even seem to miss us at all does he? We may have to come down there after him".
They picked us up at the airport in Dallas after the trip. It was funny, because as we walked up to baggage claim and was waiting for our bag, he was talking ninety miles a minute about what all he did and how much fun he had. He was chattering nonstop without even taking a breath. We got the bag and were all walking out the double doors that lead to outside. Just as the double doors opened, a really cold blast of air hit us. His talking came to a sudden screeching halt, his eyes got huge, he came to a dead stop, then without saying a single word, he just suddenly turned around and started running back toward baggage claim and the doors that lead back to the secure area. While my husband and son laughed their heads off, my D-I-L and I chased him down, yelling for him to stop. When we finally caught him and asked what he was doing, he said, "It's too cold here. I'm going back to Disney World where it's warm and I can swim every day". He then glared at me and said, "Nanna get me back on that plane and take me back to Mick Mouse". I reminded him he hadn't seen his parents or baby brother in a week and didn't he want to spend some time with them. He looked at his mom and back at his dad, who had caught up to us by that time and said, "I saw them, now take me back to Disney World right now! I'm not staying here!"
His younger brother will now be three on March 21st. We are going down there during that time and have talked with his parents about us taking him, but he is a big momma's boy and there is just no way he'd stay away from his mom that long. He'll spend the weekend with me, but by Sunday nights he's wanting to go home. We are going to have to wait until he is a little more mature. His older brother is not thrilled. He keeps telling us we need to take his brother to WDW, so he can have another turn.