Joe, when I lived in Stewart in 1975 the Stewart-Cassiar wasn't finished yet - the section around Bob Quinn was just a series of wandering logging roads that had been connected, sometimes very roughly and sometimes not even passable with my 4x4.
The northern extension of BC Rail started in 1972 and was abandoned in 1977 due mostly to grossly underestimated construction costs. Some 20 years ago you could still drive a few miles of the impressive grade at Gnat Pass south of Dease with a 4x4, but it's too broken up now (you still could with an ATV, I think).