There are passing opportunities. Going up The Hill might be easier than going down - unless you know how to manage braking on a long hill. I saw a pickup camper with smoking brakes at the bottom of The Hill.
Since you are talking about going up, but not down, does that mean you intend to take the BC ferry from Port Hardy? The drive to Port Hardy is a bit of an adventure in its own right.
Google Maps has Streetviews for the eastern half of Hwy 20. This area had a lot forest fires last summer. And one washout near the Fraser River crossing that was discussed on this board (Canada section).