let me try to address a couple of your questions, booking a guarantee can be a double-edged sword, book a cabin catagory that you would be happy without getting an upgrade, never book a lower catagory than what you would be happy with and hope for an upgrade, you could be dissapointed. IF you get an upgrade great for you. The downside to booking a guarantee is that you could end up with the lowest rated cabin in your catagory, its all about location, location, location, which brings me to the question about which deck to book on. On Princess our favorite deck is Caribe- basically the middle deck. Take a look at your ships deck plans and you be able to see where you are in relation to enterainment, dining, the pools etc.