the only way we've been able to do onsite in November with an over-7 in past years is to either use our existing APs and book room only with Expedia, or book one adult in on the hotel/tickets package and add the child's name at check-in (again with an existing AP as a park entry ticket).
Last November I just couldn't get anywhere near under budget for an onsite hotel stay, so we bought APs again (I knew we'd be using them on at least 2 trips in a year) and went offsite to the Dream Castle.