I was on the Bulkley in mid-October last year - October 13 to October 22, 2007. It was beautiful! The weather was variable from sun coming through and having to take off your coat to nasty cold with wind in your face. Be prepared for these variations in the weather. If you are a dry fly fisher you probably know that BC fish come up top for a fly even when the water is in the high 30's unlike lower 48 fish. If you like fishing tips you will usually make more contact with fish than us surface fly fanatics, especially if the water is high and off color.
Have fun and God Bless,
Todd