The Grand 1 is approximately $400 per hour which included the Captain and one crew member. Tip was extra.
We took it for a Wishes cruise which included a tour around the lake, a great view of the fireworks, and then a look at the Water Pagent. We were picked up and dropped off at the Poly, but I would guess you could arrange for any of the resorts on the lake.
You can arrange for food and drink through GF Private Dinning. We had champagne and a dessert tray which was served on the bridge. I know you can have a full meal, with a butler, if you want. All of this is very expensive, but for a special occasion it was definately worth it.
Any specific questions? I would be glad to answer if I can.