My girlfriend April and I rode out this way last July as part of our cross-con trip. I can give you my impression of Canmore-Waterton Lakes via the east side, but don't have the experience of the west side to compare.
We used Great Parks North from Glacier NP to Waterton Lakes NP,* then north up to Pincher Creek and Alberta Route 3/Crownsnest Highway. We diverged from the Great Parks North route just west of Lundbreck and headed north on Route 22, the Cowboy Trail and took that north to Black Diamond where we headed east to Okotoks and then Calgary. You could continue north on 22 from Black Diamond and then either take 1 (Trans-Canada Hwy) or 1A west into Canmore.
22/Cowboy Trail was some nice riding. Alberta's major highways all feature nice wide and paved shoulders, yet traffic was pretty moderate here. The terrain is rolling, with a couple of climbs, nothing too bad. Scenery is a mix of grasslands and ranches with some woodland interspersed, and great views of the Rockies. And there are a couple campgrounds along 22, the bigger one being at Chain Lakes.
The one thing to note about this route is the lack of services for the most part. There are no towns between the 22/3 junction and Longview, which is about 110 km or 65 miles. No people either but lots and lots of cattle! You would need to stock up on stuff at Lundbreck (but since it's a very small town, the best supplying up is in Pincher Creek with a supermarket and Wallyworld) including water. There are a couple campgrounds along the route, but the one furthest south has non-potable water. Chain Lakes has potable water, a soda machine, and a snack bar that is open sporadically. The Bar U Ranch, a historic ranch site, is south of Longview and has gift shop and snack bar as well.
And you would pass by a mile or so long fence with hats on the posts.
Here's basically what the Cowboy Trail looks like:
1A west of Calgary wasn't bad. There's a section of no shoulder for about 15 miles we were warned about, but barely any traffic (as most through traffic uses the Trans-Canada west of Cochrane) so not too bad. A few places to camp along the route as well.
The other route between the Crowsnest Hwy and Canmore would be 40/Kananaskis Trail, which is west of 22. It's supposed to be more rugged and hilly, with a long section of gravel and even less in the way of services. But it's supposed to be really beautiful. Next time if I go through this area I might try it.
*Even though the main part of Waterton Lakes is a bit off route, I would advise you to take the detour, it's worth it!