So we have gone 3 times now.
The first time we did 3 days at the parks, 3 night on the Dream, and then 1 more day at the parks.
The 2nd time we went we did 4 days at the parks and a 7 night cruise on the Fantasy, no parks after.
The 3rd time we didn't do any parks, but stayed at WDW resort, then did a 4 night on the Wonder, then went to Disney Quest the day we got off the ship.
Our upcoming 4th cruise will be 1 day at MK doing the Christmas party then 7 night cruise, then a relaxing day at Fort Wilderness then in a cabin for the night.
From our experience, doing the park right after the trip was exhausting. The first cruise I had a severe sun burn with blisters from
Castaway Cay (even after loads of sunscreen) and it was in June. I was miserable, we lasted half a day before we quit and went back to the pool to swim and relax. When we did Disney Quest we were so exhausted and tried to bribe our kids with money NOT to do Disney Quest but to go to the pool and relax. They refused and hubby and I were dragging after just a few hours. We finally pulled the parent card and said forget it, we're done. We went to the hotel, ordered dinner and fell asleep by 8pm lol.
If you can manage to take the day you get off the cruise as a day to relax rather than go to the parks, then the following day do the parks, I would recommend that. It is a very early start to the day the last day, no sleeping in.