The icefields parking lot is a hidden treasure, as far as we're concerned. We thought about spending a night but decided to continue to Jasper, but not before having dinner there and taking advantage of the various facilities available.
Although the building shuts down, there are plenty of fellow campers and so no concern with safety, and it's a big parking lot. You do have to be mindful of animals like bears when it comes to food being out. If you have plans to go into Jasper or see Athabaska Falls, this is a good halfway point.
It seems like you're thinking to commute back and forth after setting up camp somewhere- I would set a 30 minutes max 1 way, and am thinking Lake Louise to the Icefields is about 2 hours (plan extra time for slow traffic cuttings, and mountain driving). DM if we can help further, or you want pics.
