What is the traveller's state of mind?

In De La Mare's poem, the traveller is not at one with his
surroundings.  The traveller comes upon the castle late at night, with the elements all
around him conveying a sense of the unknown.  He calls out to signal his arrival, knocks
on the door, and receives no response to either.  It is at this point, where the
traveller's state of mind is confusion at both the absence of a response as well as the
conditions around him, conveying a sense of the unknown and the ambiguous.  "The one man
left awake" is shown to feature an agitated state of mind that is not in concert with
the setting around him.  The environment is not impacted by his presence as it
represents an existential state that is without essence.  The traveller seeks to find
some meaning, some purpose in this setting.  The traveller's state of mind is one where
there is question and confusion regarding the world around him and an inability to bring
the subjective to merge with the objective
reality:

The scene reinforces one of Walter de la
Mare’s common themes: Human beings are estranged from both the natural and the social
worlds, and are puzzled and even frightened by the unfathomable mystery at the heart of
life.