Congrats on your choice! How long are you gonna stay? If it's for a week or more, def. do two excursions: Chichen Itza and Isla Mujeres. Chichen is one of UNESCO's World Heritage sites, and is considered one of the "Wonders of the World". Don't miss out on this one, especially if the day trip is free!!! Isla Mujeres has the potential to be loads of fun, especially if you try to be extra adventurous and depart from the plan once on the island and leave the "beach club" area to explore the island at your leisure. Just be sure you find out where your tour departs from the docks further north, so you still get the free ride back. Shuttles to/from the hotel zone I suppose should be back fully by the time you have your vacation, as the Cancun Palace and other Palace resorts there should be open by then. These are normally stops for the shuttle in addition to stops at one or two of the shopping centers in the area. Plan in advance what days you want to do certain activities (Chichen, hotel zone, Isla Mujeres), so that you can arrange these the day you arrive at the resort. Shuttle space now is apparently by reservations only, so schedule this arrangement ahead of time.