While there are probably other groups of islands known as Gulf Islands, the ones I grew up around are located in the Strait of Georgia between the British Columbia mainland and Vancouver Island. The six largest islands - Gabriola, Salt Spring, Galiano, Pender, Mayne and Saturna - are serviced by ferries. There are also many smaller islands, some of them inhabited, some not. All are blessed with the mild coastal climate and relatively calm waters, buffered as they are from the Pacific Ocean by the bulk that is Vancouver Island.
My father, an architect, also built sailboats, and I was lucky to be able to spend idyllic summers sailing around the islands. Us three kids would pile into the 26 foot Thunderbird, sometimes with both parents, two cats, and grandparents, and head off to anchorages to spend a night or two. Or my father would take us kids off for a week or two to tour a number of islands. Sometimes we'd see orca or dolphins swimming by, and the harbours were often populated with curious harbour seals that couldn't resist coming up close for a peek at us.
The boat was pretty small and primitive, with a two-burner kerosene cooker and a pump toilet, but each morning we'd get in the rowboat and row to shore to explore our terrestrial surroundings. We'd hike around the shoreline of the smaller islands, scaring mink and alarming oyster catchers, who laid their eggs in depressions in the rock. Or we'd follow sheep trails through the Garry oaks and blackberries to peer into decrepit barns and cabins abandoned by settlers who left behind rusty pots and old magazines which we pored over in fascination. We'd pick apples from orchards gone wild, and fish for cod off the rocks, which my father would have to whack on the head to kill, then clean, so we could barbecue them on a beach fire for supper. Portland Island had wild sheep that ran from our laughter; Tent Island had warm warm water that was a joy to swim in. Gabriola had a heron rookery; the tall trees were full of nests, the ground stained with birdshit. I have a thousand sensual memories of sights, sounds, smells, and experiences of those times.
Perhaps you could charter a boat and tour some of these places yourself. It is an achingly beautiful area that has to be seen to be believed. I miss it.