We were checking out of SSR that morning, had a tropical storm impacting our evening location and got BCV for that night. Moved out of SSR at 10, checked into BCV at 11 (but the room wasn't ready until 5).
This was a fluke because we had been trying to get BCV for months before this. I think they just worked a little magic on these added days.
If you can't regularly plan your vacation at least 6-7 months out, you will be disappointed if you are planning on Oct-Dec, Spring Break, marathon time, or any of the special room locations/types of villas.
If you will take any location, any room type, you probably could do it, but with no banking for the last four months of the use year (new Rule of Four), DVC might just start moving DVC availabiliity over to CRO three or four months out instead of just 60 days out.