IMO the best alternative is to get a large cup of water at a quick service counter every chance you get because it's free and you don't have to worry about attractions that don't let in food/beverages.
Pair that with a nalgene water bottle (made of lexan... it's guranteed to not break, meaning if you manage it you send them the pieces and they send you a new one) and you've got bottomless water on the cheap
If you want water while you're at WL, I think it's free from roaring forks soft drink dispensers even without buying the mug...