Landscape as the primary force
Wilderness fiction is defined by the primacy of the landscape: it is the first and most constant presence in the story, the condition that shapes every other element. Build your wilderness world from specific, researched knowledge of an actual place: a particular ecosystem with its particular plants, animals, weather patterns, and geographical logic. Generic wilderness — the forest, the mountain, the desert — produces generic fiction; a specific boreal forest in late October with its specific light and its specific cold and its specific sounds produces fiction that the reader can inhabit. The specificity also protects against romanticism: a real place has inconveniences, confusions, and beautiful details that are not in the service of any theme.