"Nightmarish" is the only word to describe the job of booking a holiday week in the tropics for your Christmas vacation. The planes to the Caribbean and Hawaii are largely full at that time, their prices astronomic (JetBlue is charging $1,400 round-trip between New York and Aruba), and the hotels all chock-a-block despite charging their top rates of the year.
I recently dissuaded a friend from attempting such a trip, and persuaded him to enjoy Christmas in London instead. In the course of a quick, easy phone call to an airline, he immediately found seats for himself and his spouse because he was flying on Christmas Day. Apparently, very few travelers wish to fly on either Christmas Eve or Christmas Day, and the planes at that time have many empty seats.
Same with an apartment rental. I supplied him with the names of Rentalo.com, EVrentals.com and Coach House London (chslondon.com), all of them specialists in renting short-stay apartments to tourists, and he quickly discovered that such lodgings are plentifully available from Christmas to New Year's, a time of year in London when business visitors stay home and not on the road. For 100 British pounds ($158 a night), he easily found a centrally located, one-bedroom apartment in London with a fully equipped kitchen, and living room with television.
I warned him that London virtually shuts down on Christmas and the next day (Boxing Day), and since he was arriving on Boxing Day, I urged him to have a pre-reserved car service meet his arrival at Heathrow Airport and drive him into town. I told him there was a real chance that he would be unable to find taxis for that purpose on Boxing Day, and that subway service would be unusually sluggish. He made the reservation. I also told him that most grocery stores and restaurants in London would be closed on Boxing Day, and he therefore made arrangements with the apartment owner to pre-stock the refrigerator with coffee, milk, butter, bread and eggs, a couple of steaks and containers of flavored yogurt for dessert. He made those arrangements.
So my friend will now be enjoying London during a week when the city is quiet, but the theaters and museums are all operating once Boxing Day has passed. You might want to consider a similar vacation for yourself.