While "any" would be a better word choice for this sentence, either can be used for more than two options. It's just not very common.
It may not look like it... But there is only 2 options at this point, go forward or back. It's part of a larger hiking trail and while this stretch looks still pretty tame, it gets quite challenging in the mountains, so even experienced explorers stick with the paths here :)
I should really have said "While 'any' may be a better word choice..." since I didn't know the context.
