It's a long hike that can be shortened by taking the boat and saving a few miles. I think it is among if not the best views in the park. It can be backpacked if you want to stretch it out, but I don't suggest backtracking.
You should know that at least some of the Canadian border guards consider bear spray "a weapon" that needs to be declared. I always keep mine at hand when crossing so that when the guard asks I can just hand it to him or her to check the brand. Yes, only certain approved brands are permitt...
In Assiniboine Provincial park you can catch a bus from Banf that takes you to the ski lodge. From there hike two days (or one very long day) to Lake Magog where there is a large backcountry campground near a backcountry lodge (at the base of Mount Assiniboine). From there there are several absolute...
Assiniboine Provincial park, just outside Banf, and Robson Park, just outside Jasper, have some great hiking. Copelands' book "Don't Waste Your Time in the Canadian Rockies" is a great resource.