Nov is my absolute favorite time to go. It has been our best trip weather wise. Cool nights and cool early mornings then it warmed up in the afternoon so you could take off your sweatshirt. Perfect weather for park touring, no humidity at all. We had one little rain shower, but it was when we were sleeping at night. We went the week after thanksgiving, it happened to be a year when Thanksgiving was early so wound up leaving on Dec 1st. It was perfect, and very low crowds.