While flying through this valley, which I have done maybe forty or fifty times, I always stuck well over to the starboard side. Not much use though if others don't do it.
I must say I occasionally feel the Canadian TSB reports are of doubtful quality. Inevitably there is going to be some level of speculation in GA reports where information is limited, however phrases such as "The aircraft may have been close to overloaded," (Which I have actually read in a TSB report!) are worryingly worded and imply guilt where none is established.