Here's the experience from our recent (Dec 15-22) trip...
We had a DVC reservation from Dec 15-21, a CRO reservation from Dec 21-22.
I called DVC MS and they noted that the DVC reservation was a 'continuing reservation' and included the CRO reservation number. They gave me the standard 'we cannot guarantee that you will stay in the same room' disclaimer.
I also called CRO and had them make the same 'continuing reservation' note along with the DVC reservation number.
I fully expected that on the morning of Dec 21 we would have to 'check-out' of the DVC reservation and clear the account of any incidentals, and then 'check-in' to the CRO reservation. We were also prepared for the possibility that we would have to switch rooms, and could even be without a room between 11 and 4.
What actually happened was far better - perfect actually.
When we checked in on Dec 15, we were told:
- we would stay in the same room
- we wouldn't have to check-out/check-in on the 21st
- our key cards were stamped through to Dec 22
- our parking pass was good through to Dec 22
So - it was as if it was all one reservation. Wonderful!
All that said, YMMV! Do that cross-linking, be pleasant at time of check-in, and it may all go swimmingly for you too!
HTH, Jeff