We are leaving on Saturday and when we arrive, need to stock up for the week for 4 adults so will need adult beverages as well as food and water. Where is the Walmart in relations to the Grand Mayan and is taking a taxi there and back the best way? What should we expect to pay for the 4 of us R/T? Also, is this a super walmart where you can get anything under the sun? Thanks for your help everyone!