This is a fantastic multi day trip that starts around the Columbia Icefields Centre.
The trail is moderate in difficulty, however, the distance is what makes it difficult. There are two river fords on this trip; however, one river you must ford twice. The first river is maybe ankle deep (I would imagine much deeper in spring runoff), however the second river is something to contend with, as it runs almost waist deep if you arrive later in the day.
All things considered, you won't meet many people on this trail, and it's definately one of the better trails I've ever done. The trail is in Great condition the whole way, except along the second river ford, where things get a little confusing, but the trail is easily enough picked up afterwards, and you're back to the fun hiking.
There are three passes on this trail, but only the Jonas shoulder is trying. The Jonas shoulder is the culmination of a very long alpine day with a valley and glaciers that will knock your socks off! It's well worth the trip.
Directions:
The trailhead is technically in Banff, about 8km South of the Banff/Jasper Park Boundary opposite Parker Ridge. If coming from the south, the parking lot is at the top of the highway switchbacks climbing up from the Sunwapta River. The parking lot is marked with a map at the trailhead and is the trail to Nigel Creek/Pass.