Has anyone done this trip this past year? I know there are several roads closed around the Comox Lake Area which makes the traverse challenging.
I haven't been around the back of Comox Lake this year, but there are private cottages along the north shore of the lake so I'm not sure how that road could be closed to all traffic. Once you get to the end of the cottages it's a pretty short run on any actively used road until you are away from the lake on deactivated logging roads towards Port Alberni.
Personally I don't stop riding when I see a "road closed" sign. If I did I'd never get anywhere on Van Isle. I've run into logging company personnel numerous times on "closed roads" and not one time has anyone been upset with me being there. They are just curious WTF a guy on a bike is doing so far from anywhere. That said I do interpret "road closed" signs as ride at my own risk and "get the F--K out of the way of any trucks/equipment!" because they are working and not looking for cyclists. If I figured a section of road was actively being utilized and I still wanted to get through I'd just be there at the crack of dawn and get through before work started for the day.
That's ^^^ just my personal take and not what I am saying anyone in particular should do. You have to evaluate your own risk comfort zone and do what's right for you.
If you can't get around the back of Comox Lake you can follow the Eastern portion of this loop to get around to Port Alberni and rejoin the route: https://ridewithgps.com/trips/1305947
Although there is a sign on this alternate route that says "Private Road - No Trespassing". A bunch of rich folks have fancy houses on a lake in this area and the road doesn't go anywhere in their minds so they don't want riff raff driving into their enclave. I ignore the sign and pedal through. I'm only on a developed road for a few minutes before things get remote/wild again. Nobody has ever given me grief when I have done this.
