Yes it will be fun. I went a few years ago during Christmas season. Love their shopping, and love the Christmas lights! But lots of snow! Must wear rain boots, otherwise your shoes and feet will be all wet.
on your own is good enough, subway is pretty convenience. just ignore the peak hour. and nov is start to get cold, no smell la.
you may join a local day tour for those "must see" attractions, and rent a car to the outlet. you can take train to the outlet, but if you are planning to shop a lot, car is better la.