Please note that I am responding to your question privately and off-list, as we try to avoid airing on the list itself controversies over faith matters that have nothing to do with the Greek text itself.
Regarding the accounts of the Gerasene Demoniac in Mark 5 and of the Fall in Genesis 2-3, I am indeed very much inclined to understand them not as historical events but rather as instances of theological exposition by means of story-telling. Please understand that I see profound and fundamentally important truth in both stories, but I don't feel the need to affirm that they describe events that happened at a particular time and place in the continuum of human history; rather I think that they are (1: the Genesis story) a truthful account of what happens in the course of every human life as we rebel against God and assume control over our own existence and so are alienated from God and become self-willed and morally helpless until we accept his gracious intervention on our behalves, and (2: the Gerasene story) a story of whaat happens in Christ's encounter with just such a demonically self-willed and morally impotent person as the healing rescue come to that person; this is precisely w
hy I feel it is comparable to Romans 7:14-25: I think that both passages describe the same condition of unredeemed humanity and the redemption that comes through Christ.
Personally I have no problem with scriptural authority, as I am not a literalist or fundamentalist and my own denominational authority (Presbyterian -- UP{USA}) does not require of its adherents (nor of those ordained as clergy or elders--I am an ordained elder--belief in the literal historicity of the Biblical text.
This may not satisfy you from the perspective of your own faith stance, but I did want to clarify to you the perspective from which I wrote that note.
Regards, cwc