I think you will still have a wonderful time! The ship will be easy, the main things people spend mega bucks on is adult beverages, excursions, pictures, and bingo. You can have the best trip ever and not spend one cent on any of those! The more difficult part of the trip will be the land portion. I'm assuming you have park tickets. Food can be pricey, but there portions are big and my kids often share meals... Just watch your money. Tell your kids in advance that the TRIP itself is their gift and not to ask for souveniers. I make my kids save their own money for souvies and I think kids of any age should be able to appreciate that as long as they are told in advance

. Souveniers are NOT a necessity. I think your girls will have such a great time, that not getting souveniers will NOT be a problem.