I don't know if the times change during different times of the year, but we have gone every October. I brought back the DTD guide map from this past trip and here is what is says:
West Side:
Dining & Entertainment hours 11:00 a.m. - 12 midnight
Shopping hours 10:30 a.m. - 11:00 p.m.
Pleasure Island:
Dining & Entertainment hours 7:00 p.m. - 2:00 a.m.
Shopping hours 7:00 p.m. - 1:00 a.m.
Marketplace:
Dining hours 9:00 a.m. - 11:00 p.m.
Shopping hours 9:30 a.m. - 11:00 p.m.
Again, I'm not sure if they change these times during the year.