Of course it's always subject to the weather but i know here in Colorado that some of the areas always try to be open for Thanksgiving - at least on a small run basis. I'd think that maybe some of the Canadian FTers could suggest Whistler since i thought it opened pretty early and had the glacier fields. Since that is always a pretty iffy time, if I were you i'd get married and do the honeymoon a few weeks later when the snow conditions are pretty much guaranteed, though Thanksgiving is always the busy start of the season.