Just checked the website for you... the Renaissance Grand Beach does appear to be available for your dates, and even an upgraded room certificate is available if you want to go for the extra points. (I checked May 27 with a checkout of May 31. Are you actually looking to checkout on June 1? Shouldn't matter.) The Cayman Islands Marriott appears available, as does the Puerto Rico Stellaris Casino location in San Juan. Go to the website, pick your location, click "make reservation", and after you put in the dates, scroll down a bit to where it offers "Marriott Rewards Redemption Certificate". Click a check in that box before clicking "Go" and it should give you the Marriott Rewards Redemption option. Let me know how it works, or if I can help with something else.