I did the same Los Angeles-Vancouver in an Embraer 190, although mine was a later flight which left me with around 45 minutes to go through Canadian customs to join the Sydney flight. Customs basically just gave me a stamp in the passport, and gave me a transit card to give to another customs person who escorted me upstairs via a lift to the departure lounges.
The gentleman who checked my boarding pass and passport at the departure gate counter commented that my birth date was exactly the same as his.
I suggested that this would be a good excuse for a free upgrade, and to his credit he did look in the computer, but unfortunately there were no seats available.
All staff at Los Angeles, Vancouver and on the planes were very helpful, but one thing I did note on the 777 to Sydney, the entertainment screen on the back of the seat in front of you only had the basic channels, and no games to play, so I couldn't get in my 40 rounds of mini golf per flight.
