That's the one I was thinking of and couldn't remember the name.Try Turner Drug. They deliver (for a fee), but melatonin seems like a product the resort/park gift shops would be unlikely to carry. Any supplement, really.
For Melatonin users out there, I recently tried one formula that also includes L-Theanine to enhance the sleepiness and it definitely made a difference. The brand I tried is Nature's Truth but there's probably other popular brands that offer the combo as well.
This one is 10mg Melatonin, 5.5mg L-Theanine. Even with being very small pills I can bite them roughly in half. Still plenty powerful enough to knock me out Strong!