The Cowichan Valley is on Vancouver Island and in the Province of British Columbia The Cowichan Valley Regional District has 2 routes with go through it.
The Rotary Route, which extends through to Nanaimo / Saanich / Duke Point / Tswassen
And the Cowichan Valley Regional Trail.
http://www.bikemap.net/route/162391
http://www.cvrd.bc.ca/index.aspx?NID=121