The best site for anything and everything cruise related is
http://cruiseforums.c...forumdisplay.php?f=83
There will be 2 formal nights- children expected to be smartly dressed-you can always adapt their school uniform if they don't own a suit. If they are girls then I'm sure they'll have party dresses. They will want to look smart in front of the US kids who really do dress up nicely.
Eastern itinerary is easy to DIY providing you have done your research.
Pick your destinations from this list:
http://cruiseforums.c...orumdisplay.php?f=587 and read what others have done and private tours they recommend.
Finally the best facility on this site is their Roll Calls - this is where you can chat with others on your cruise, perhaps find friends for the kids, and if you are lucky someone will already have done all the planning and you can just join in.
http://cruiseforums.c...orumdisplay.php?f=261
You have to be a member to see this bit, but it is free and the amount of info you will get is invaluable.
And she is a ship not a boat......