Great to see you back here, Vida!
Well, you've got a really nice challenge here, don't you? How to reveal a Disney Cruise family reunion surprise! What an awesome event to look forward to. Based on my personal experience, it is easy for the kids. All you have to do is pack their bags in advance, bring them to the airport and play a scavenger hunt. Revealing the surprise in pieces helps too... they'll feel like it just gets better and better. You'll be chuckling every step of the way. Who knows - you might even want to put up a scoreboard now - for the kids to collect points, and EARN "the surprise" for April 2015. You won't be able to pull that off with your parents though -- since they'll need the notice to prepare themselves for a trip (medications, packing, shopping, etc). But, having a cruise-themed party for one of their birthdays, or the holidays might be nice. And then having them open the "gift" as a highlight of the party. Or, you can always do a Pirate-themed party... shop for pirate gear for the whole family -- have a treasure hunt, and a treasure chest with the big 'reveal'!
I'm sure you'll think of a fun way to present your surprise. Even how simple it could be -- you're giving them an awesome gift as it is. There's nothing like a Disney Cruise vacation, and you and your family will have an unforgettable voyage with Captain Mickey!
Pirate Night is a signature party only found on the Disney Cruise... you'll surely want to prepare for that. I'm sure you can now picture your family all geared up and taking those awesome photos on the cruise in their pirate attire -- I am so thrilled for you just thinking about it!
Have a magical time planning your pixie dusted voyage!
~ Dolly