I have no special knowledge of the highlands, but in comparing them to the North Cascades I would observe that the North Cascades do not have peat bogs, and if the north of Scotland has any similarity to western Ireland, the possibility of peat bogs would indicate to me the desirability of waterproof footwear of some description.

Also, the photos I have seen lead me to think that the highlands are much more barren of trees than the North Cascades. I would think that this would make sheltering from wind more difficult.