Achluophobia - The Fear of Darkness can be easily overcome by seeking this cache under different conditions. The first step is to find it in the winter when the brightness of the snow will allow you to see your way into the darkness - once your eyes adjust. Then come back in the summer after the trees block out the most of the light. And then for your final test, come back at night and grope around in the dark.
Also known as Myctophobia or Scotophobia. But distinguished from Claustrophobia, the fear of confined spaces, i.e. you don't need to go into any tight space to obtain the cache.
Do not park on the roadway. Instead, park at one of the nearby parking lots and then walk, ski, or snowshoe to the cache.