Welcome to the boards.
This a great place! Ask any question ever and you get good advice from great people!!
I have 3 1/2 year old and 18 month old boys. We have done
WDW and DLR and many other trips around the world. I suggest starting early and plan a nap/rest time in the middle of the day. Bring snacks and lots of water or juice. Be ready for a meltdown or two at some point and have a plan as to how you want to handle them. We try to be really consistent with time-out no matter where we are or what we are doing.
Happy planning!!