Hi, I was told we could pre check-in 8 days to 3 days before arrival. If I were you, I'd wait til you arrive at the resort to arrange the day and time for your dinner. We've been to CN 4 times and have never done the private dinner. We like being able to just go where we feel like - when we feel like it. We've spent extra on a night dive, the gift shop, the spa, but never for the dinner, the food is so good everywhere and we'd rather not have sand in our shoes after dark. And I wouldn't want anyone to have to trudge through the sand with food, drinks, etc. to get to us. Yes, you can book the dinner in the tree house, but I'm the kind of person who wouldn't want anyone to walk up and down those steps to serve us. The staff is so wonderful that they would do anything to please the guests, but they already work so hard that I won't add more for them. Can't help it, just the way I am. Have a great trip! We always do!!
i usually do the pre check in 2-3 days in advance and have never had a problem. you should be okay making the reservation once you get there just do it right away to have more choices of when you would like to have it