I would second the December-January time off for interviews.
November is a bit early and you won't have heard from some of the programs even if you apply early. With that info in mind, I would take off December-January, because you will have heard back from most of your programs by then and can decide which interviews you may want to cancel and which you will go on. Of course, if you plan a light month in November, then you could still squeeze a few interviews in that month as well.