Welcome to this thread! I beleive you can either get married in the gazebo or just off to the right of it on the little sand place. I'm not sure if they allow you to get married anywhere else. You could really do anything you wanted after your ceremony until the time you have your supper. By the time you have your ceremony, champagne, and take pictures, I don't imagine you would have more then a few hours before your supper. You could go to a bar, relax by the pool, go to your room and take a nap!
You can rent to gazebo for the evening. Some of the other brides on here will know more about this as we chose not to do that, but rather I think we will just head to the disco or something. Our group is a bunch of party people so I'm sure no matter what we do it will be fun! We are making OOT (out of town) bags for our guests. We are using a tote bag and adding some other things to it. If you search on this site you will find lots of ideas for them if you chose to make them.