I also have a 3 year old and was wondering what to do on the Nassau day. My husband wants a place to go gamble in the casino for a while and the Atlantis is the only one I am hearing of. We would just take a taxi over. That is def the way to go. We went to the Alantis about 5 years ago and had a blast. But that was because we had access to the slides, and lazy river, pools, etc.
But it sounds like now the only way to get a day pass is to actually rent a room. Can you not even walk through the hotels acquariums and pool area etc unless you are a guest? Back then I remember them saying that the beach area out side the hotel was a public beach. I am not sure if it still is.
I know my 3 year old would love Atlantis's water area but it sounds like we won't be allowed there and I'm not even sure about the beach.