This might be a good question for the main Princess board, where people know the ships really well.   We've done Alaska on both Grand and Island, and have been on Royal in the Caribbean, but none of it recently. Grand at the time (2015) was a bit run down, but the crew was terrific and we had a great time. Royal and Majestic are newer and bigger but that's not necessarily a plus in Alaska. The verandas on Royal were tiny compared to what we had on Grand, so personally I'd pick the smal