In the St. John's area, for some routes there are significant differences between what's displayed in online maps, and the ones in the HB. I'm not convinced that the online maps are right -- for example, Mapnik has NL 11 coming within spitting distance of Cape Spear (easternmost point in Canada), while my notes from my 2003 visit there and the HB have Cape Spear as much more distant from NL 11. If the HB routings are based on fairly recent shapefiles, fine.
I'll add that in Labrador, where online mapping was really sketchy when I was there in 2011 and is probably a little suspect even now, I took handheld GPS readings of most of the route endpoints. They all match up nicely with what's in the HB. (I didn't whip out my GPS receiver nearly as much on NAewfoundland island.)
Also, in the southwestern corner of the province, NL407 has a waypoint labeled "Sea" (for the Searston community),that is at an intersection with a secondary road (which I traveled, for no apparent reason other than perhaps a road closure north of Searston) for which online mapping shows route number 407-1 but no name. Elsewhere I've noticed the HB often uses road names rather than secondary route numbers. and I'm OK with that preference. But where we have no road name available, I suggest using the secondary route number.