We just did this a few weeks ago, and it worked great.
Some thoughts.......
I booked it when we booked the cruise, and then checked the rate a month before our cruiese, and it had gone down about 30%. Make sure you understand the taxes and surcharges. They added about $50 to the price of the room, but still worth it.
Taxis are a dime a dozen. The standard rate is $4 per person, and a dollar for tolls. I negotiated to $15 for four of us, and he brought us right to the Comfort Suites. (Sometimes the taxi waits for other passengers to fill the taxi. I always say that I want to leave now and not wait for others.) As I was getting out of the taxi, I told him that I would give him a twenty if he brought the rest of my party right to Atlantis, and I would meet them there after I checked in. It is only a 5 minute walk, but we had an ouchie ankle in the group, so it worked fine.
We were at Atlantis from about 11am-3pm. There were halloween activities at 4pm that we wanted to be back for. We could have stayed longer if we wanted, but we had done all we wanted to do, and were not quite to the waterlogged feeling that sometimes creeps in at the end of a waterpark day.
Getting back was easy, let the bellhop call a taxi from Atlantis' front door.
One other option is the water taxi, but they typically wait for a large number of passengers before leaving. I think the price is similar, but the walk to Comfort and Atlantis is probably 1/2 mile.
As far as food goes, we had a rolling cooler with us, and ordered room service sandwiches and chips and took that with us. I know that everyone's moral compass is a little different, but I did not personally see any restrictions on this. (Don't flame me please. I have read many posts where there is a difference of opion on this, and I respect all of your opinions.) I did not bring fruit off the boat, and the cooler was never searched. We bought beer and Goombay Punch for the kids at a store near the port, and had cold drinks all day long in the cooler.
My wife priced out a lunch for the four of us, and it would have been at least$50. Maybe have a huge breakfast, and eat a snack when you get back to the boat to avoid overpriced mediocre food at Atlantis.?.