I was there recently after a suicide attempt not related to DID or trauma so I'm not sure what they would be like regarding those issues, but I will say that Sheppard Pratt is a decent hospital. I HATE hospitals and would never voluntarily go again, but SP was great compared to others (the food was mostly edible, you didn't have a roommate, and the 'group leaders' actually tried to teach/engage you so it wasn't as boring). At other hospitals you really do just sit around all day - but at SP they had some games, books, and art stuff which made time go by a tiny bit faster.
I do remember that one patient there found the "women's group" the most helpful for working through some of her trauma, but unfortunately that was only once a week.
Good luck to you.