Yes, I can testify to the persistence will work. I checked the reservations 3-5 times a day for single nights at a time. They sometimes posted openings at 3pm Eastern, even. I also called a few times for the after Jan 1st dates and the reservation cast members were very accustomed to people calling to find cancellations--very helpful and not at all annoyed. After about a week I was able to get all 7 nights, through the week of New Year's, on four separate reservations and had them linked together.
That being said, we were already pricing out our other options. We stayed at Port Orleans Riverside last time and this time we were going to try Coronado Springs as the backup. We loved staying on site, using the magic bands, bus system and everything Disney offers...I don't think we would want to try staying elsewhere, even if we couldn't camp.
-e