I just returned from our trip (Fabulous!) and I thought I would answer my own question in case anyone else wanted to know :). We did book a room at the Comfort Suites. With taxes and everything it wound up about $350.... still cheaper than the Disney Excursion for the three of us. We were allowed off of the ship at 9:30. We took a cab to the Comfort Suites ($4 per person). Cabs were plentiful right outside of the ship. We checked in and checked out, walked out of the back door, went to Atlantis and got our wristbands. It was sort of a long walk from the place you get the wristbands to the waterpark, but it was inside the hotel so we got to see the hotel itself. The walk from the Comfort Suites was right across the street. We were inside the waterpark by 10:15. We saw the Disney group arrive much later... about 11:00. We did everything we wanted at Atlantis and headed back to the ship about 3:00. Another $4 per person taxi. Taxis readily available outside Atlantis. I would definitely do it this way again. Not only was it cheaper, it was super-easy and we could come and go as we wanted. My son really enjoyed the slides at Atlantis as well.