I've got WC Cal King bagged in '07 as a neonate. He fed fine until around september (as I recall) then got real fussy, then turned-off altogether. One night, sometime in November, while messing around trying to find a way to get her interested I accidentally left the top off for a while and when I came back she was gone. I found her on the crawl in March, a little bit lighter but no worse for wear. She then fed well until a around early August and turned-off again. She has barely lost weight but I've had enough of the bullsh*t and so put her down for the winter along with my Western Hog which does the same thing.
btw, both snakes get especially hyper when they turn-off and I think it is because they are searching for a route to a hibernaculum rather than for food.
Hope that helps ease your worries