Flight
Nanaimo is the closest airport to fly into. Victoria is another option but it is an hour away from the Cowichan Valley.
Travel Note
Driving to the island takes about 12 hours from Calgary. The ferry from Tsawwassen to Duke point is the fastest.
House Or Rental
There are many vacation rentals offered on VRBO or Airbnb around the Cowichan Valley. Suitable locations for accommodations would be Duncan (15mins), Maple Bay (10mins), Ladysmith (20mins), Cedar (25mins), Cowichan Bay (18mins), Shawnigan Lake (30mins), and Crofton. I have compiled a list of places in these areas.
Hotel
8 Double Queen Rooms have been blocked from July 21st to July 25th ensure you mention Kennedy/Smithson Wedding to get the discounted rate.
Discount Code - Kennedy/Smithson Wedding
House Or Rental
Osborne Bay Resort has a studio, 1 bedroom, 2 bedroom, and 3 bedroom cabins for rent, full service camping is also available along the ocean. These cabins and camping spots book up fast.