I have to disagree- there is no point in getting to the pier too early and waiting in line then.
I always plan on arriving about 1-2 pm and just walk on, since most people were waiting in line earlier to board.
Just a thought, Vancouver is a great place for some quick touring as well. You have found the 3 transfer options available.
there also likely is a cruise contracted bus. I most always drive, but took Quick Shuttle with no complaints one time.