Another vote of Magical Journeys! We did our first DCL on the Fantasy over Christmas, it was INCREDIBLE! We loved every minute of our cruise. We have done 3 more cruises since then, 2 more on the Fantasy and one 4 night on the Dream. As for the shorter cruise, we felt "cheated" not spending the full 7 days on board, So for us our next cruise is another 7 night one.

Our boys are a bit older then yours but when they were your guys ages we booked CAT 4D, for not much more. This sleeps 5 instead of 4 but has a Murphy bed and a shower "stall" instead of the tub/shower. We went for the larger room since the bunk will only hold 200 lbs. The boys will thank you for the bigger beds.

Another piece of advice, book your next cruise on board, you get a 10% discount and an on-board credit from DCL. You can put as little as $250 down for a place holder and make a reservation anytime over the next two years. What the place holder does is allows to book a cruise without reserving an actual date. You can then research the perfect cruise when you get home. We book a place holder as soon as we can once we board.