Just got back from an 11 day cruise with our 18month old daughter. Here are some things that made our experience on the Golden Princess enjoyable.
We had an outside cabin with a window that DD LOVED climbing up in - the bed was directly below so if she fell, no harm. Next time, we'd like to try a balcony room so that at least we can enjoy the sun and outdoors while DD sleeps or plays in the room (ie a totally confined space)
We put her crib (a fold up, rigid version, not a pack-n-play as I was expecting) in the closet area. It was like she had her own room and she (and we) slept much better than if she had been right next to our bed. The crib only took up half the closet, all of her clothes hung above it, and our hanging clothes had plenty of space also. And lest you think this is weird, the closet area in our cabin was just that, and area, not an actual enclosed closet. You had to walk through it to get to the bathroom.
We enjoyed the mostly enclosed kiddy play area on deck. We could relax as she played and not fear her running away.
We started out with "Anytime Dining" but ended up with a standing reservation since we had a large family and always wanted to sit together. We preferred this since our waiters actually got to know us and our daughter's preferences. The head waiter spoiled her and my cousin's boy - age 4 - with special desserts and the like. It was great. And on the rare occasion that she was too fussy to finish dinner, our waiter had dinner sent to our room for us.
We went on one all-day excursion and she did great - for the most part. It was a Pirate Ship Adventure and she loved the boat ride and the beach break. But she hated the life jacket she had to wear for the transport to and from the beach. I would say that when it comes to 1/2 day and all-day excursions with your children, it really depends on your children and the type of excursion. You really are the best judge of what your children can and can't do. That said, I was very glad in one port that we were not on an excursion because she got sick and we had to go back to the ship much earlier than we expected.
We brought about 4 sippy cups and it was great. We always took two to the dining room with us, one for water and one for milk or juice. Then we always had one with milk in our little fridge.
We took our kid carrier back pack, but did not use it as much as I had anticipated. She was much more comfortable in her stroller where she could lay back and sleep. And being in Mexico, the stroller was much cooler for her than the carrier. But, there were also times when I wished we had been able to use the carrier because we couldn't go everywhere we wanted to with the stroller.
And speaking of strollers, we have the Graco Mosaic. It worked great in the tight quarters of the ship and in port. It also is big enough to carry some essentials for port days and for baby to lay down and sleep in. It folds down nice and small for storage when not needed, but is also small enough that they way we had our room situated, it just sat in the corner and gave our rambunctious daughter something else to play around on.
Well, I think that's about it. I hope some of you find this helpful and I hope you have as wonderful of a cruise as we did!