It's getting harder and harder. I would not wait much later than the 90 days out, really. Just to make sure.
They do require a deposit on this one, too, so you might get lucky and snag a cancellation right before the cancellation time is up for people wanting their deposits back... This one def books several weeks in advance, and I've never heard of anyone getting in a coupel days before or that day (though pixie dust does occur on occasion!)
We LOVED this breakfast! Good luck!