So weird - I was going to recommend Honeymoon Island too! We are visiting a local friend before WDW and we just went there today. Very nice. Calm, peaceful water. The kids snorkeled. There is a big sand bar that you can easily walk out to and it is super shallow again.
I drove from her house, but I think it should be pretty easy to get to.
It was really nice. Cafe, bathrooms, outdoor shower, kayak, umbrella and chair rentals too.
Kim