The only TS I can think of that has a carryout window is Beaches & Cream, and they don't offer food or specialty sundaes to go - just beverages and small ice cream concoctions. They have a banana split you can order to go but it's not available as a
DDP snack. They do have shakes there you can get for a snack credit - but you must get them from the takeout window, not inside the restaurant.