My memory tells me that the bus (the blue ones you get on at the foot of the gangway for lots less money) takes about two hours. The accuracy of this recollection may be somewhat fuzzed as "the thing" is reporting to the Red Dog Saloon immediately afterward. We did.
Maybe move your whale-watching back a bit?
At each port, it's a good idea to send someone off the ship immediately to see if you can't get a great deal on what you want to do. There are little "newspapers" mostly filled with tourist activities at great prices.
Maybe Mgram can tell you if whales tend to keep "office hours" the way that dolphins do.
You're sure that there's not room for me in the cabin?