. Is there a smoking vs. non-smoking side to the ship?
No, but the dining rooms are smoke free as well as the Windjammer. I was on the Navigator and I was never bothered by smoke, except some minor annoyance in the casino, which is to be expected.
2. Are the Cat C (Junior Suites) worth an extra $850 over a D1 balcony for a family of 4 (2 small kids)? Pictures don't really seem to show the cabin being all that much bigger...?
They are bigger and the AFT C Jr. Suites are the BOMB. Awesome views. The best thing about the C when you have little ones is that the C has a bath tub and most little ones don't care for showers. Really nice sized walk in closet that gets things out of the way, which also leaves the cabin appearing more spacious.
3. Are the Aft facing cabins (specifically the Deck 10 Junior Suites / Cat C suites) 'better' than a port/starboard facing regular Junior Suite? The balcony looks bigger but less private. Is the view good? I like look at shore!
The aft view is a great view and I am sure you would enjoy it. The balcony is larger too. However, a side-C woudl be fine too. Just try to get it as mid-ship as possible, closer to the elevator the better...no there won't be noise!
4. Are the 3rd and 4th berths in D1 and/or JS
via trundle, off-the-wall, or sofabed? I think C's have sofabeds and some may have a pull down Pullman style bed, which your 6 y/o would love!!