I will partly disagree with the others in the post.
Does DVC work great for those who cannot plan ahead - no!
Can it work for last minute travel - yes if you are willing to accept the limitations that will be imposed.
Do not expect to get into VGF, VGC, BCV, AKL-Value, BWV-Standard, etc and during the mid-Sept through mid-Jan time frame.
You will most likely end up at SSR, OKW, or AKL for all your trips and only one - three days in a row at any one location.
Some of my last minute trips have included:
DW and I several times have been at DS (old DTD) for the day and decided we wanted to stay the night. Called the resorts directly (back before MS was open on Sundays) or MS and checked in within 15 minutes.
At MK for the day in Feb ’14 for our anniversary, called MS @09:00, and booked a room at BLT for that night. Checked-in @11:00 and the room was ready. We did not plan on this day going like this until @05:00 while still in bed.