One word of caution...
The only gas station on the Icefields Parkway between Lake Louise & Jasper is at Saskatchewan River Crossing and they are simply put gougers when it comes to gas prices.
That place is a disgrace to the tourism business, they know they are the only establishment for 100km (60 miles) in either direction.
Their prices for everything are sky high and at one time they were charging more than 30 - 35% more for gas than either Jasper or Lake Louise and those prices are at a premium.
Make sure you have a full tank before leaving either Lake Louise going north or Jasper going south.
I admit I haven't been through there for 18 months but for the 3 years before that I drove it (both ways) summer & winter about once a month.
I'm sure things haven't changed.
Happy travels, drive safe, watch for animals
Cheers,
Geoff