In a parking lot.
Sorry Les, I could not resist. I can't say that I have had to drive to Vancouver, so I can't offer any real advice. Maybe someone else can.
If no one offers up suggestions, I would say to start a Google search and find out what you options are before going. There are ports that have not cruise line or port affiliated parking companies that offer parking at a reduced. Maybe they offer that in Vancouver.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013