Holy shit that is an epic area. I have never been up Illecillewaet during the winter, but damn does it look amazing. You could also look into renting out a back country lodge, somthing like the Wheeler hut, or the Asulkan hut. The Asulkan hike in is a long way though, and it goes through some dangerous terrain. But once your up there the line are damn near limitless.
Like nomensteven said, go to the discovery center, pick up a topo map (have one right in front of me) and pick up the ski touring in Rogers Pass book. I got one of those and it give detailed routes to great lines, and how to avoid getting loss.
I have never been to the pass but am planning a trip around Rememberance day, it looks like it's been continually dumping at the pass, so I think they'll have enough snow. I have heard of an area called balu trees or something? Not sure where that is, but if it's snowing then like it is now I might have to hit up the trees, is there anywhere good to do quick (fairly ) laps of them, and will the alders maybe be too big in November.
And how much a night is that best western, don't want to repeat the harrowing drive every day.
And what about those huts, do you have to book them like a year in advance.