To speak from experience...in 2009 we took advantage of the exact same free dining incentive as we just today booked for this year for the same exact time frame. We arrived on the day after Thanksgiving, had a room-only reservation for Fri and Sat (not free dining dates) and then had a package with tickets and free dining beginning on Sunday. We are doing the EXACT same thing this year. In 2009, when we checked in on Friday, we were given not only our park tickets and room key on the same card but also
free dining for every night beginning that moment instead of having to wait until Sunday. It was supposed to be difficult, and I thought we would have to return to check in again on Sunday - and NONE of that happened. I am optimistic that this will happen again, but won't hold my breath. Be prepared for the worst case scenario, but don't fret about it. I worried for the worst and the CM thought I was crazy expecting to be inconvenienced by coming extra days and therefore spending more money on property!

Be sure your reservations are linked together via a note in their system.