I have lived on Vancouver Island since I was 16 ,. Apart from a couple of Years working on the lower mainland and travelling all over BC as a part of My Job I would say that that is most of My Life!
I'm now nearly seventy?
There are still places on the island that I haven't got to yet!
If You just want to see Victoria and do Butchart Gardens in a couple of Days ,leave Your Vehicles in the US and walk onto the Coho ! Ride the City buses or take one or two of the numerous Tours!
Unless You have a Few weeks to spend don't bother bringing Your Rig over at all! What You will save in ferry fees will pay for some nice meals and a decent Hotel Room!