I've published a trip report about recently driving from Seattle to Alberta and back in mid winter.
I've included lots of ancillary information about the area, including about other seasons too.
See Lee's Random Ramblings: Seattle to Alberta in Winter

Well done! There have been several posts lately about driving this or a similar routing lately in winter, and this will be most helpful. Our experience has been mainly early fall, with some very early/late summer, so we've been able to venture into some B.C. roads that wouldn't do very well this time of year.

Marking your site for future use, thanks bunches.