I don't read "House Fear" as reflecting a loss of adventurous spirit due to fear. The poem is indicating that the people being described have a certain level of caution or concern about what they might find upon entering a dark house during the night. Because of this fear, there are certain rituals that must be observed every time ("ALWAYS") - they needed to make noise upon entering and left the door open until the inside light was lit.
Some readers might conceive of these practices as indicating a loss of adventurous spirit. Part of the answer may lie in your definition of what constitutes "the adventurous spirit." Are the people being fearful and cowardly instead of adventurous and brave, or are they simply being responsible in the face of the unknown?