Rode the Northern extension of the GDMBR from Hinton south to the 1A highway. 460 km, it took us seven days of riding. Its as tough as any of the original Great divide sections, but the routefinding is easy, just follow the 40/734 all the way. Lots of very steep gradients up to 10% on gravel. Not much in the way of amenities, the hamlet of Nordegg has a couple of gas station/convenience stores, but they were pretty depleted when we passed through. Heavy industrial truck traffic in some sections, but the professional drivers were courteous.
Scenery is more foothills than high mountain peaks, but low cloud, fog and smoky haze made it hard to see much.
Lots of good camping alternatives, both in provincial campgrounds and random camping. Some of the campgrounds were closed for the season, which allowed us the experience of being the only campers in the large Ram Falls campground, surrounded by dense fog , and virtually no traffic on the road. It was eery.
I'd recommend it if you are ready for a tough gravel road through remote country, but be prepared for gravel, mud, dust and steep grades.