The possibility of moving to Prince Rupert has come up. I'm unable to find any real mention of any riding there. From what I can tell it looks like the closest trails are an hour East in Terrace. The only real mentions of mountain biking in the area I can find are a couple of articles in local papers from 2014 about locals looking for land to build trails, and a BCBR video on YouTube where they end in Prince Rupert but it looks like they ride in Terrace and have a banquet in Prince Rupert.
Is it possible this is the only city in BC with no mountain biking?