You can see there is a post missing immediately before the last one (John’s). The reply I’m guessing I would have made is also gone.
I had stayed in Banff that year, mid-late March (included Easter), along the main road into town where most of the hotels are. The bus company did an excellent job at providing enough vehicles to cover all the pick-ups. Sometimes one bus would be full up by the time it left the previous stop and another (empty) one would have started two stops further on, but another would be along in a few minutes to fill in the gap.
Around breakfast time, if you missed one departure for Sunshine or Louise, it would be a lot less than an hour before the next. (I don’t remember the exact timetable.) I dare say there were fewer to Banff’s local hill (Norquay), and few to anywhere after the morning peak. There was an after-slopes-close bus back from Sunshine but 16.30 was the last I remember from Louise.
Whistler, with its biggest-and-best reputation, I’d say doesn’t really match the original requirements for late snow (not at the bottom of the mountains, however good it may still be at the top) and reasonable cost!