The PCL depot in Victoria is on Douglas St at Belleville. It's a 4 hour journey (by car, by public transit/walking on the ferry or by PCL) and has to be the most convenient public transportation available. In Vancouver it arrives at Pacific Central Station. Here's the map of what's involved, Zoom it in for detail. What is your hotel in Vancouver, for advice of how to get there from PCS.
Just to give you an idea of the differences between public transit and PCL. Transit would take 1 hour from Victoria to Swartz, then walk on the ferry, then walk off at Tsawwassen (a long overhead walkway) to the waiting #620 Bridgeport Station bus, then transfer right at Bridgeport to Canada Line rapid transit down to Waterfront Station in downtown Vancouver. #620 + CL = 1h25min. PCL would involve getting to the bus station and onto the coach, 45 min drive to Swartz arriving 15 min before loading, priority loading for the bus into the bow of the ship, go up on deck to enjoy the scenery, go down to the car deck to board the bus, priority off loading for the bus, 1 hour into PCS.