We booked via JetBlue and had two nights in a hotel to bookend the cruise (Caribe Hilton and La Chonca). Uneventful travel down to SJU via nonstop from BOS. Did a little site seeing in Old San Juan - very nice feel to that area, old buildings and nice people helping out with directions and suggestion on where to go what to see.
Getting on the this very big boat (boats are for fun, ships are for war - in my terminology, sorry) was not that bad except for the "locals" cutting in line, not being prepared with tags on bags etc. Carnival may want to have a few lines for the different processing - those with bags checked by porters and ready to go, those with no clue as to prep and carrying bags. I would say it took about 1.5 hrs to work through the line. Again not horrible considering the number of people getting on.
Once on, we headed directly for our room. We had a corner cabin on deck 8 with a huge wrap around deck - very nice. We then headed off to find the "hidden doors" and explore. We did find the layout to be very odd at first but we got used to it quickly. The odd parts are that "you can't get there from here" at times. One might have to go up or down a few floors to get to a destination. Again not horrible at all and we should have brought our on deck plans. The maps by the elevators and elsewhere are not as informative. We had a cocktail in one of the bars which was empty and headed off to the Lido and upper decks. This was our first indication that some of the previous posts had warned about - lots of locals (Puerto Ricans) onboard. I would guess about 80-90% locals. Nothing was going to bother us at that point and just kept right on having a good time and exploring.
Large wrap around balcony, watch out for debris falling from above though.
Bath Vanity needs some work - ugly 50's pink.
Very quiet - most of the time.
End of hall - long walk to gangways off the boat.