Easy call to ski Fernie over Kimberley.
I agree with this too. Fairmount Hot Springs is a nice place to stay halfway between Kicking Horse and Fernie (2 hours from each, with Panorama 1/2 hour detour). Castle is 1 1/2 hr detour from Fernie on that route.
Your route is the mirror image of ours last year that started on President's Day:
Whirtefish 1 day
Fernie 1 day
Golden 2 days (1 Kicking Horse, 1 Purcell Heli)
Revelstoke 1 day
Liz was in Revelstoke 3 more days, skied 1 there and 1 Silver Star with a day off while I was at Mustang
Day off driving to Nelson, 3 nights there, skiing 1 day Whitewater, 1 day Wild Horse snowcat, 1 day Red Mt.
Overnight in Rossland, didn't ski another day at Red because it had rained, so ...
Day off driving Rossland to Bozeman to ski the next 4 days at Bridger/Big Sky/Moonlight.
Some of this depends on your driving tolerance. We had a very long day driving Sun Valley to Whitefish to start that trip, so putting in another 3 hours roundtrip to Castle when we had a fixed date needing to be in Revelstoke I thought was too much. Without my year-ahead Mustang snowcat reservation we would have gone slower and gone over to Castle, and maybe even thought about Panorama on the way to Golden.