You might want to consider the Rockwall Trail just on the other side of the Continental Divide in British Columbia’s Kootenay National Park. There are a few entrances and exits so you can fashion your own trip. Did the whole thing about a decade ago and it was pretty amazing.

Plenty of day hikes as well. Would recommend Sentinel Pass from Moraine Lake to Lake Louise.

Waterton Lakes further south has some amazing day hikes as well.