You must get a hotel + ticket + DDP package in order to get the DDP. In addition, the DDP must be purchased for every person in your party in the room, for the entire length of stay (number of nights). Your ticket could be as many or as few days as you want. You DDP must equal the number of nights staying in the hotel. Example:
5 night stay=5 CS meals, 5 TS meals, 5 snacks per person in your party
You may get a 6-day MYW ticket because you can go everyday to a park including the day of check-in and day of check-out.
For our stay in July, we opted for a 5-day ticket and not the 6-day since we knew we did not want to go to a park on check-out day. Still got 5 days on the DDP with our package.
In addition, your DDP meal and snack credits will not expire until midnight on the day you check out so you could still use any remaining credits that day at the parks if you want!