HMH begins on September 16 and carries through to January. IASW Holiday will begin on the first 'official' day of the holiday season, which we
think will be 11/11/11 this year, though it could be 11/18/11.
In any case, you will get to experience both (if your trip happens, that is!). The Reindeer Round-Up will be open. The snow will be falling on Main Street. The Winter Castle will glow in icicles at night. Even Storybook Land will have its tiny Christmas decorations on the miniature cottages. ToonTown, A Bug's Land, New Orleans Square, Frontierland and Main Street will all be decorated in their own unique styles and the holiday music will be playing. Gingerbread cookies with mouse ears will be sold. Santa will be in at least 4 locations all over DLR (probably 5 locations), and the glorious GCH lobby will be abuzz with holiday splendor, as carolers perform by the giant Christmas tree, a guitarist and pianist play holiday favorites and people get cozy in the comfy chairs and sofas (or by the fire) with snacks and beverages.
Come join us over in the
Disneyland at Christmas Superthread!
My trip will overlap with yours - though I am not staying at GCV. I will arrive on 11/28!
Just booked the GCV for 3 nights at the end of November for a trip I'm not even sure we'll take 
Will IASW holiday and HMH be running by then? Not even sure this trip will happen but predicting we'll be at the sucky Las Vegas Turkey Shoot soccer tourney again over Thanksgiving and didn't want to miss the chance to cruise down to So Cal as we'll be 2/3 of the way there from Utah. 
It's fantastic. I have TONS of reading to do. In all the years I've been going to Disneyland, I have never had a fresh candy cane or been to the Reindeer Round-Up. So much to look forward too. 
And the GCV at Christmastime is unreal. We stayed at the DLH in 2005 over Christmas and visited to GCH. Heavenly.
