I put your start/finish into my browser maps and came up with Creston, Cranbrook, Invermere, Radium Hot Springs, Lake Louise, Icefields Parkway to Jasper, Yellowhead to Prince George.
Beautiful route with terrific towns/campgrounds the whole way. Would definitely be my first choice.
I've been the other way as well, the Creston-Salmo pass is steep and slow, pretty scenic from Nelson to Revelstoke, but won't make great time. Also about 200km longer than the route I proposed, if that matters. Both will be fun and beautiful, can be dicey in the winter months.
I'd be happy to provide campground recs if needed.
