If you do Waterton, I would suggest camping at Bertha Bay - a backcountry site right on the lake. You would need to get a backcountry permit at the Warden's Station which is just before you get to the townsite. You can store all your panniers and extra food in the bear lockers at the far end of the townsite campground. There's a bathhouse with showers there, as well. Then it's only a mile and a half hike to the campsite - although it does climb a chunk. The townsite campground has 843,000 people - Bertha Bay may have 8. Last time I was there I was all alone.