Yeah, both Whis and Sunshine have spring passes. If you can get to Whis for Telus... it's a hell of a party and usually has pretty good weather. As it gets into the actual spring in Whistler, it's known to rain quite a bit.
It's super easy to hitch to Sunshine from Banff. Whis is super convenient if you're staying in the village or creekside area, but sometime's you've got to walk quite far into the village/hill. There's always bus stops not too far if you're not into using your feet.
Revy, Silverstar, Big White, Whitewater, etc are all really sick but they won't stay open late regardless of how much snow they get. Sunshine would stay open later but the national park makes them shut it down. Whistler/Blackcomb shut down in late May regardless of snow coverage because they switch into biking mode for the summer, aside from the glacier of course.