A few notes on cabin 2612: This was our first cabin with a connecting door. When we booked via Costco travel, we had a noise concern with having a connecting cabin and were considering a non-connecting cabin further aft. The agent told us that it was nothing to worry about and that the connecting cabin wouldn't be any louder than any other cabin. Wrong.
The connecting door is thin, and you can hear everything going on in the other cabin. Our cabin neighbors had young children and my wife and kids were awoken virtually every morning by the kids. Mind you, the kids were not obnoxiously loud or in any way out of control. They were just being young kids-- they talk, they laugh, they play. But man, you could hear every bit of it.
Also, there was some kind of pump or servo motor in the vicinity of our cabin that would activate for several minutes at a time at random intervals throughout the day and night( sounded like it was in the structure below our cabin between decks). It was loud enough to wake you up and was quite annoying. We never determined what it was, but it would definitely keep me from booking that cabin in the future.