The Holiday season usually starts in mid-November, somewhere around Veteran's Day (11/10/17, 11/10/16, 11/13/15, 11/13/14, 11/12/13). Dapper Day is slated for the first weekend in November this year (11/3 and 11/4).
It seems like there really aren't that many periods in the Fall when the parks aren't busy anymore. HalloweenTime (which usually starts in early-to-mid-September) is the kick-off and crowds, especially on the weekends, seem high through the Holidays (early-January). There maybe a few days here and there that aren't that bad (mostly weekdays), but they seem hard to predict. While early-November might be between seasons, I would try to go either before Halloween (to enjoy the HalloweenTime offerings) or after the holiday start (to enjoy the HolidayTime offerings). Early November seems kind of that middle time, when the parks are transitioning (IaSW might be closed to have holiday overlay installed and SM might be down for one or two days to remove the Ghost Galaxy Overlay).