Hi, Per. No one has yet mentioned Wilmore Wilderness Park: https://albertaparks.ca/parks/central/willmore/
Willmore is outstanding for long, spectacular ridge walks. Check our RaysWeb: https://www.raysweb.net/willmore/pag...psandmaps.html
I don't think Ray is updating this site any longer, so some links don't work, but it is terrific for photographs and descriptions of the area.
I have backpacked and horsepacked into Willmore. On one trip of 10 days, we did not see another party until we crossed the Jasper boundary, and even then at only one campsite.
In wet conditions, the trails in the Willmore valley floors close to the trailheads can be quagmires at stream crossings due to horse traffic. But once you get away from the main trailheads, or if you travel along the ridges, conditions are pretty good.
The front ranges of the Rockies east of Jasper and Banff comprise mostly Provincial land with many opportunities for random camping: https://www.alberta.ca/public-land-use-zones.aspx
I have horsepacked into Blackstone/Wapiabi and didn't see a soul for a week other than our group. Travel on foot through the Blackstone or Wapiabi gaps is tricky because the horse trails plunge in and out of the rivers without consideration. But it should be possible to find foot routes that don't cross so often. The rivers are wide and mostly pretty shallow in late season and it would be impossible to get lost if you followed your own path through the gaps.
The trailheads to all of these places are generally accessible by car. Some trailheads may require high-clearance vehicles. Once you have some candidate locations in mind, call Alberta Parks to ask about trailhead access: https://www.albertaparks.ca/albertap...bertaParks.ca/
I have found the Parks people to be very friendly and helpful about these things.