Last time I drove the route there was no place to fuel between Lake Louise and Jasper.
Fill up at the Petrocan in Lake Louise NOT the Husky--Petrocan is often cheaper.
Since you are coming from Seattle I would take the south route and come up through the Kootenays and visit Radium Hot Springs. Stay in USA for as long as possible for much better fuel prices.
From Radium to Lake Louise there are no powered campsites and no cell phone service (except at one "store")
I find Banff to be a "tourist trap".
I love Miette Hotsprings and there is a Campground at the bass of the mountain on the road up to the springs. It has no power--but there are good washrooms and showers. There was no attendant last time I went there. It runs on the honor system.