Walk up to the cm in front of the que and ask if the captain could use some help piloting the boat. If no one else has asked, he will say yes (only 4 people allowed to go at a time). Then you wait and the same cm you talked to will walk you up to his cabin. It's a great experience!
It is such a great exoerience for the kids! Another cool thing is you get to sign the book that is in cabin. The captain also gives great history of who has all been riders up top. Don't forget to take your camera...there are alot of amazing shots from up there!