I'm so glad we extended it. I just started to relax around day 4, so if I had to get off on day 5 I think I would have been in tears!
So, for the first leg, we had cabins 7419 (L-shaped room) and inside 7421. My sons were able to keep their room for both legs. We moved to an aft balcony (7427) for the second leg. My kids had a key to our room so they could enjoy the balcony whenever they wanted. I posted photos of both rooms in the Carnival forum.
Cabins:
7419: L-Shaped cabin with extended balcony. Great location, quiet, room layout great, lot's of storage.
7419: inside with beds in L shape. Was roomy and comfortable.
7427: Aft balcony (just next to the wrap balcony on Empress Deck)... great location, quiet. Balcony hot on most days...not much breeze back there.