Don't know about pre 1969, but the Sidey's early 1970s summer included scheduled stops at normally one gulf island on either the north or southbound leg of a round trip.
Now, 1976: full time four boat service was maintained on route 2 until after fares were nearly doubled by the Bill Bennett Socred government. Ridership went way down, and service on route 2 was cut back. But there were still four ships on the route, except for refit times. I was a regular rider through those tears, and the two stretch ships on the route were normally Burnaby and Nanaimo.
It was Cowichan (dep Bay 1) Burnaby(Dep Bay 2( Coquitlam (hs bay 1) Nanaimo (hs bay 2) ---route 3 was New Westminster (langdale 1) and Tsawwassem (langdale @) Sidney was route 9,
Summer was full time four boat service, rest of the year base service the 2 Cs, with the Victoria class boats (THEY WERE NOT B CLASS the b class did not yet exist) sailing fridays and sundays. May have been 3 boats when Burnaby and Nanaimo were in refit. When the Cs were in refit a modified three boat baseline schedule was operated using the other C plus Burnaby and Nanaimo. There may have been other short term deployments on the routes, but that is basically how it ran.