You've gotten some great advice here, but I wanted to add that I've had a couple of experiences with the "hub carrier" stopover rule that differ from what vysean and planeluvr were quoted, i.e. I've been allowed stopovers where I've arrived on a random *A carrier and departed on the hub carrier. If you have the same luck I did, that would open up some carrier/routing possibilities for the first leg of your trip, which could mean the difference between getting it ticketed and not getting it ticketed. So it's worth giving it a shot if you haven't already.
Also, adding to vysean's routing suggestion, I'd recommend checking AC for award seats--either for the first leg if you find that flexibility in the hub carrier rule, or for the last leg if you don't. In my experience they've had the best availability to/from the specific stopover points you've mentioned going to/from the west coast (connecting in YVR).