In this practice they would trace the paths, or "songlines", that their ancestors took, and imitate, in a fashion, their heroic deeds. Merriam-Webster, however, identifies the noun as a 1908 coinage referring to "a short period of wandering bush life engaged in by an Australian Aborigine as an occasional interruption of regular work", with the only mention of "spiritual journey" coming in a usage example from a latter-day travel writer.
I also prefer to use the term "Walkabout" in tandem with the word Spiritual, since that seems what the majority of people are engaged in nowadays without even realizing it. They seem to be wandering in the wilderness without purpose or direction. Which, I suppose is their business, but why do they have to be so cruel?