We decided after Thanksgiving last year that we wanted to go to Disney on December 18th - 22nd (less than a month out). I looked at the availability tool, and there was nothing available in a 1 or 2 bedroom for our dates. I started checking the availability tool multiple times per day and picked up days as they became available.
I could have had a 2 bedroom at SSR, OKW, BLT, or VGF for our dates. Other resorts had a few dates open up, but not the whole time. It was weird, but in all the time that I checked the availability tool, I never saw an opening for Jambo House, or Wilderness Lodge.
We decided on a split stay at SSR and BLT. We got great dining reservations and even got FP+ reservations for the Mine Train.
It was a fantastic last minute trip.