Bob,
We plan to bring all our "big guns" for the upcoming Alaska cruise. My wife will have her Canon DSLR and I will have my Canon mega zoom (65X optical zoom). We wouldn't take them to the Caribbean or Mexico cruise but for scenery in Alaska, I'm not going to just rely on the cell phone to zoom. Need to lug the equipment around to try and catch the few "wow" pictures.
As for Mayflower Park, I stayed there many years ago. Very nice place. Just know Seattle is like San Francisco - very hilly. If you plan to walk around downtown Seattle (given the parking problem, walking is the best option), have some oxygen tank ready when you walk back to the hotel...