Just a quick comment about something disneyholic family posted in this thread.
I think whatever time of year you go there will be a lot of kids on the ship. Obviously summer and school vacations will see the most. We were on the 9/1 4 day on the Wonder and the cruise director said there were over 700 kids on board, from 30 different countries.
Since other countries have different school vacation times, and parents in the US take their kids out of school, there will be kids.
As for which to do first..... if you are going at the end of August or early September it will be very hot!! I vote for doing the cruise after the parks, because after doing the parks for 3 or 4 days you will, most likely, be beat and need a rest.