Thanks Essxjay, tom911, and ozstamps,
My US flight arrives at SEA-TAC Fri at 11:30am, so I may not mind the leisurely pace of the ferry to Victoria/Vancouver, especially if it's a nice day. Coming back Sun I'll be catching a red-eye to PIT, thus I also won't be in a hurry. Perhaps the compromise of train/bus heading up, and ferry on the return trip with an afternoon stopover in Victoria...
PS. I'll also be staying at the Renaissance Harbourside.