When my kids were that little, a trip to visit grandma and grandpa was the "cat's meow".
They lived about 60 miles from Knott's Berry Farm, Disneyland, the beach, and all the other "attractions" southern California had to offer. Southern California and Orlando would both be wonderful for little kids.
I would take them on a cruise ship. Lots of the modern cruise ships have multiple pools, water slides and kids clubs. They always have lots of food choices and entertainment for the "little ones."
We stayed at an all inclusive for those 16 and older, but there are lots of all inclusive resorts that welcome little kids. We had a wonderful time and the food was GREAT and abundant.
For all inclusive resorts in the caribbean, go to cheapcaribbean.com.
I hope you have a wonderful time. Good luck to you and yours.