we've travelled with our daughter a lot since she was born - now 4 - did a cruise when she was 26 months and a week in Canada at 14 months - and of course, at this age, every month makes a difference in some respects.
Anything she uses (pacifiers, sippy cups, special blankets, etc.) bring extras. As you have a cooler in the cabin on
DCL, you can keep some milk or juice or water cold - Plenty of swim diapers.
We really like the safeline stroller/car seat - very comfortable and FAA approved so we just strolled right on to the plane with it, then the wheels "pull up" like landing gear, as it were, and it's a car seat for the plane. Then stroll around the boat in it. No gate checking, etc.
Our daughter didn't really care for the shows at that age - would tend to go to sleep.
We never hesitated to use a babysitter when we were on RCL - I guess the option DCL is Flounders nursery - which sounds very nice - I'd concur that I'd book a sitter as much as you want - we used one at least a couple of hours every night. We'd bring our daughter to dinner for a bit then back to the cabin - I guess on DCL there are only a limited number of spots and so I guess there's an issue about being greedy with "Flounders" time - but my guess is they don't run out of openings too often so I'd book for as often as you want. I don't know if there is a minimum number of hours or not - as noted above, we booked a sitter for two hours every nught (we had late dinner seating). (I know family members of my own who would never have left their toddler with Flounders or a babysitter hired on board a ship - their preference). Anyway, on RCL cruise, at 26 months, she had just started to have an interest in TV/videos so that was good entertainment with the sitter [now we have the portable DVD too - great invention] so your daughter may or may not be entertained by one of those now.
Our daughter has never been on a particularly strict schedule - so in some sense vacation wasn't a change of schedule which I read bothers some kids - she napped when she wanted and we worked with that (sometimes she napped in the stroller - which was fine afterall). Obviously you have to consider what excursions might be possible/not possible given the toddler's age (our 26 month did the stingray thing in Cayman - not that she'd remember but we're going to do it again this summer at age 4 - so might remember this time) (we didn't book through the cruise line either time -
www.captainmarvins.com)
I think good advice is to be flexible - just in case - things may go just fine and you'll get to do everything exactly as you've planned - but maybe not - in fact, don't plan too much and then you are frustrated if things go poorly - I know on DCL there's the "pressure" to get the reservations at Palos, etc. but it sounds as if you might go one night and the other couple the other?
New toys/books for the plane, i.e., a new surprise prior to anticipated boredom. We encouraged use of pacifier at that age on the plane as really helped with the pressure in the ears. We were/are always very quick to remove our daughter if she is crying, etc. from any situation where the noise might bother people and others would have an expectation of this not occurring (especially, for example, a show). (get aisle seats, too). Always have an exit in mind just in case (alas, there's no where to go on a plane - we were always very lucky - until last trip at 3.5 - of course, no more pacifier then - and the air pressure changes did hurt her ears - as it was late at night and she was tired - if she had been asleep she may not have noticed). At the 26 month age, we splurged for a room with balcony on RCL so if child was napping, etc., we could enjoy the scenery, but DCL more expensive and so we're trying inside cabin for first time in lifetime - but we anticipate our 4 year old will never leave the kids' club! So we can use whatever deck we want to watch the ocean.
