We’ve been up in the northern Highlands (near Dingwall) – ground conditions were fantastic until about Wed then there was a bit of a thaw and a full refreeze on Ne’erday so a lot of water ice formed (rather than frozen ground which is ace). Coming home today down the A9 there was fresh snow above probably 550-600m in the east and sleet at Drumochter and it’s all set to freeze again tonight. Obviously conditions in the west are going to be quite different but based on this week’s experience I wouldn’t fancy it as a bike myself.
In summer it’s probably under 2 hours from Kingshouse to Kinlochleven but in winter, who knows really. Depends how much snow and ice you meet.