December room offers - how late usually valid?

[NewbieMouse]

We are Disneyland regulars (go every year) but are considering a different December trip next year which incorporates WDW instead (have been there once but can fit it on with a larger driving trip in the SE). With the Canadian Resident ticket offer (which must be bought by February 7th), I know you can call and have that combined with a package, but right now naturally there are no room offers for December yet. So I am thinking that I should buy the tickets, and wait and book the room separately. The question I have is - how late in December would room offers typically be valid, if they come out at all? We'd be checking out by December 20th in any trip model I'm coming up with, and would be staying at Yacht Club or Beach Club.

TIA for your help.