Interesting proposal about linking Vancouver and Prince Rupert.
https://www.cbc.ca/news/canada/british-columbia/vancouver-prince-rupert-highway-proposed-9.7247905
I'd be curious as to how far inland the highway would be. This probably isn't what they have in mind, but I think right along the coast would be very difficult with very mountainous terrain and numerous fjords and other water crossings; however, looking at the terrain on Google Maps, following the western edge of the Interior Plateau might be more plausible. Roughly speaking, it could go from Houston to Pemberton or Lillooet, with the southern most section having the most challenging terrain.
Being from Alberta, think a BC version of the Forestry Trunk Road which largely follows the edge of the Rocky Mountains.