She wandered the wilderness for days.
The leopard stalked its prey through the wilderness, pouncing with precise timing.
The bear lived in the wilderness.
wilderness
They enjoyed camping in the wilderness.
Yes, "American wilderness" should be capitalized because it is a proper noun referring to a specific geographic area. However, "wilderness" in general would not be capitalized unless it is the first word in a sentence. So it would be "American wilderness," but "But how about wilderness."
wilderness
The botanical garden has turned into a wilderness.
"With few supplies and limited food, John found the wilderness a bit intimidating."
living in the wilderness is a good place to be to avoid cosmopolitan.
I look forward to our next foray into the wilderness.
Forty years (Numbers ch.14)
Sure. "The explorer explored the wilderness. Unsure if what he'll find."
The first sentence of hatchet is -Brian Robeson stared out the window of the small plane at the endless green northern wilderness below.