In her 2009 doctoral disstertation, "An Insect View of its Plain": Nature and Insects in Thoreau, Dickinson, and Muir, Rosemary S. McTier makes the following claim about the meaning of the line:
In “A little road not made of man -” (J647/F758), Dickinson reveals that even
though her observations of nature have allowed her, “Enabled of the Eye,” to perceive
A little Road - not made of Man - [poem quote continues]
My understanding of this is that McTier is saying that Dickinson herself is "enabled of the eye" i.e. has vision to see an otherwise invisible "road". As the following lines make clear, this road is a breeze, being traversed by insects, and so otherwise could not be seen except by virtue of the animals using it. Dickinson was fond of riddling poems, and the "little road" as a zephyr feels like an extension of that inclination.
On a personal level, while this seems like a plausible explanation, it does raise a further question, because if that is the meaning, it's expressed in a very bizarre syntax. Using the adjective "Enabled" at the start of the line would gramatically be read as applying to the preceeding object - the "road", whereas McTier claims we are to understand it as applying to the poet herself. This is poetry, of course, and thus not always subjugated to the normal rules of grammar. And yet, riddling or not, it feels like a particularly vexatious choice which itself demands an explanation which I fear I cannot provide.