This may sound silly, but my knees and back have never felt better and all I ride are hardtails. Actually sold my Cannondale Prophet to help fund my TransAM 29'er. After riding both FS & HT's, for where I ride; I find a steel hardtail with a 17"-ish chainstays and some tubeless tires around 20lbs (+/- 3 or 4lbs) ... and you're golden. Really no need for a full suspension. Between the steel frame and the supple rear tire, you'll feel like you have a few inches of travel working behind ya.
I can definitely see a full suspension bike being almost mandatory for riding up in Newfoundland. A fatbike with a suspension fork would be the cat's meow for up there too. Although I guess ridgid would be perfectly fine since you'll most likely be trudging through snow anyway.