I did this for our granddaughter two years ago. She was six. It was the pirate cruise or the princess tea and she wanted the pirates. She takes after her grandmother! Anyway, she absolutely LOVED it. My daughter-in-law was very worried about leaving her only child to complete strangers for two hours but you can see the boarding and disembarking from the "shore". So no worries there.
Get there at 9:00 when the marina first opens. You can get some great photos of the new pirates before anyone else shows up. Go down to the end of the dock and you can have the castle in the background. You will be given a pager and a receipt when you check your kids in. You will need both to get your kids back. The kids have to wear life jackets. You will help them to pick them out. A Cast Member will check the fit before they board the ship (a pontoon boat with a Jolly Roger flag).
The pirates will be gathered at 9:25 and given their instructions. At 9:30, they will be boarding. Each pirate will have a buddy. Our granddaughter was paired up with another little girl about the same age. They will sail off and come back at 11:30. You have to be there to see when they land. It's hysterical. I won't give anything away but if you have a video camera, use it.
They do come back with "treasure" and the rest of their lunch because I didn't see any kid that actually ate the bag lunch provided. They were just too excited.
It's one of the hidden treasures of Disney World. To Buzz & Woody - the ages are 4-10 so your kids would be perfect. They would be together for the entire trip.