I received the 40% discount email as well.
I called and was able to book a Magic Kingdom View room at the CR for 5 nights with tickets and the dining plan. I saved about $1000 - which is actually a much better discount than I would get with
free dining (for 3 adults for 5 nights free dining would save me about $585).
Needless to say I was thrilled to find out that it was not a room only code and the DDP could be added to this wonderful discount.