For a first-timer, or even a third-timer, a tourist backpack could still have value.
For comparison, a recent F/B post from Washington State, where No Parking on side of road is in force, sort of:
So, yes, it looks like the entrance road to the Berg Lake trailhead on a nice weekend in August.
Which is why I aim for shoulder seasons and hope it snows, to deter others, but not too much! Last September no site on BLT was full, and Berg Lake campground itself was probably 1/3 empty when I was there. The hike in from the North Boundary Trail looks like fun, less so on my own. (Also, I think the bus back to Jasper has been discontinued; am not sure.)
I am looking forward to next year's visit, to try out some of Howesthehike
's backpacks and range more widely from tourist-bespoke areas. I've picked up more ideas already from this site than I can put to use. So thank you to everyone for posting!