Agree with Toto, a cab or a water taxi ride is worth the ride to the Atlantis. If you want to see the "Dig" , you can purchase a ticket for about $25. If you don't want to see the "Dig", you can still walk around the grounds and the hotel/casino.
In order to get to the pool area and grounds, you must go thru the casino. And they will never refuse anyone from the casino area.
Carol