My son went at 4 and 5 and I'd say the other kids were 5-8 years old. He did the one at YC and GF. They were similar in that they used clues to look for a treasure. The one at YC goes into Epcot though and they get out in Canada and chase a pirate. They get a snack and drink while on the boat. They get to wear a pirate life vest and are given a bandana at the beginning. When they find the treasure everyone gets a bag they fill with the little trinkets. Rings, fake jewels, necklaces, etc.
At almost 8 I'm sure my ODS would still enjoy it. Not sure about at 11, but I'd ask them what they think.