My understanding is that if you book with DVC points and ask to change your room, there is a penalty fee to pay, so asking for an upgrade might be more than just the difference in the rooms. Be sure you know what you have to pay before you make the deal so you know if it is worth it to you.
I agree that the secret porthole rooms are not secret any more and so are harder to get. When we booked our October 26, 2002 cruise, 9 months out, I asked specifically for a hidden porthole room by room number. The DVC fellow had to put me on hold to go see if it was available but it was not. None of them were for my cruise. But if you want one, ask DVC about availability of those 6 cabins by number and expect to wait while he goes to check. We then asked for the category 11 room that we had on our first
DCL cruise and it was available so we will have a reunion with that room this time.
I understand that DCL staterooms are larger than on other ships and from the one that I stayed in on
Royal Caribbean I found it true. We had no couch and only one straight chair that was for the vanity. The cabin seemed cluttered all the time and there were only two of us. Hard to watch TV in that room too, but they had no channel from the bridge which is our favorite on Disney, so it was not a big deal.
Have a wonderful time. No matter where you stay it will be great.
Jan

& Tom
