For our Wishes Cruise, we ate at Whispering Canyon in WL at 5:30pm and told CM we had cruise and we made it in plenty of time. I went to check in while other took their time since cruise left at 7:30pm. Another option is to order from in room dining at WL and they will bring it to the boat for you. I ordered cake, coffee, tea, hot chocolate and they delivered for us. The full menu is on allears.net
We had a great time and really enjoyed it, it was a birthday surprise for DS. After the cruise, the CM brought us to GF so we could take monorail to TC and transferred to Epcot monorail to beat the crowds at MK for the buses. Worked great. Have a great time.