Another simple trick is to carry an empty "QuickTrip" or "RaceTrac" 44 ounce drink cup with a lid+straw with you on-board. With the free drink stations, we've found that this cuts down on the amount of times you need to keep going back/forth to the drink stations for refills.
I do this as well, but one thing I want to advise for those who have not done this...fill one of Disney's cups at the drink station and then pour it into your mug. Keep doing that until your mug is full. It helps prevent the spread of a virus. Use a clean cup every time you got back for a refill.
On the lines of things to do that are cheap...it's about $6 to rent a bike for a ride around CC. Our family does this every time we cruise. It's a really inexpensive excursion.