We stayed at CBR in November 2016 and our visit overlapped a back-to-back room discount and a free dining promotion. (Granted, the "free" dining required us to upgrade to parkhopper tickets and a preferred room -- pretty typical requirements for moderate-resort-free-dining-offers, so by the time we added in those extra costs it really only amounted to a 40%-off-DDP-discount rather than "free" dining for the days we had it, but still better than nothing!)
The free dining promotion began on 11/15, the day AFTER our scheduled arrival, so in order to be eligible for it we had to split our booking into a one-night room-only on 11/14 (when a room discount promotion -- I think 20% -- was in effect), immediately followed by 6-night a room-and-tix-and-"free"-dining package. Since we made our room-only reservation at the same resort and same room category as our package reservation, we didn't even have to switch rooms (although we did have to go through the charade of checking out and checking in again at the front desk).
Just a tip: the available rooms go FAST when a free dining offer comes out. If you have to switch your reservation dates like we did (meaning you need to call in to WDW and can't simply make the change on your MDE account), don't even bother waiting on hold for hours to get through, only to find that all the rooms are gone, as my TA did. Just get online while there are still "free dining" room available and book an entirely new reservation, and then cancel your old one.
Regardless of your method, if at first you don't succeed, keep trying back -- I was advised by some folks on this board that often, additional free dining rooms get released about 2 weeks after the initial group of rooms is released. Sure enough, exactly 14 days after the "free dining" offer for my dates was initially released, I checked the Disney website early in the morning and discovered that more free dining rooms were suddenly available at CBR. I booked a whole new set of reservations online and simply canceled my original one.
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