Depends on what kind of performance you're looking to get out of the laptop. Realize that, unless you're willing to put out big bucks for something designed for gaming, you're not going to be getting perfect performance on resource intensive games. If you're okay with playing future games on medium or lower settings and at a sub-par framerate, go for it.
BC is more of a summer province; it's pretty miserable around this time of the year. I'd say you're already making the most out of your trip by going to Whistler. There's enough stuff for you to do in Whistler for a week that I doubt you'll really need anything else to pad out the trip.