What a great family vacation! We cruised with our oldest, now 9, when he was 10 months and it was fantastic. The crew all loved him so much and were so accommodating. We brought our larger stroller and it worked out great for us as that is what he was most comfortable in. We used it to take walks around the deck probably more than actually taking it off the ship. He also slept amazing on the cruise!!! I remember at the time saying we just needed to stay on a cruise ship for the kid to sleep through the night. We did use the pack and play that the ship provided. We sent diapers through amazon to our hotel that we were staying at pre cruise. It saved us a ton of space packing and they were fine keeping the package there till we arrived. We loved our beach time and I'm sure you will too. Have a great trip!