The Floor of Heaven

It is the last decade of the 19th century. The Wild West has been tamed and its fierce, independent and often violent larger-than-life figures – gun-toting wanderers, trappers, prospectors, Indian fighters, cowboys, and lawmen –are now victims of their own success. They are heroes who’ve outlived their usefulness.
But then gold is discovered in Alaska and the adjacent Canadian Klondike and a new frontier suddenly looms - an immense unexplored territory filled with frozen waterways, dark spruce forests, and towering mountains capped by glistening layers of snow and ice.

The Darkening Sea by Alexander Kent

Kent's popular naval hero returns to England after the capture of Martinique and finds a brief respite in the arms of his mistress, Lady Catherine Somervell. But a new conflict looms, as France forges an alliance with America, threatening British trade routes.