Perhaps you may be aware of the Trans Canada Trail main website:
http://www.tctrail.ca/home.php
Not familiar at all with Newfoundland for that part of the trail.
The trail is envisioned to cross the whole of Canada west-east whichever direction. I haven't looked recently how far north it jogs up and down to south.
Surely pieces of the Trans Canada Trail exist in Montreal area, are paved/ not so rough. I know in Toronto, whole sections are along the well-known Waterfront bike route along Lake Ontario. I've seen the signage as a cyclist from years ago.
And there is a whole book just exclusively on the Trans Canada Trail for British Columbia with detailed descriptions of trail route and pics. It was a gift to dearie one year from moi.The piece through Metro Vancouver which includes the suburbs is abit complicated and goes through some forested hiking areas that would not be accessible to bikes. (or it would be downright dangerous by falling off a mountainside cliff)
So it varies in terms of pavement/surface quality, signage across Canada. Some sections aren't connected since dependent on funding and work effort.