I generally don't try to see things metaphorically in scripture. I try to take whatever seems like it should be read historically as history and I try to read things that should be read literally as literally as possible. I don't think many of the people I end up talking through scripture with really understand that about me. People seem to think that I just want everything to be read metaphorically and that, perhaps similar to many of the conclusions of the "Jesus Seminar," nothing in the bible actually happened. I don't think that at all. The only difference between me and many of the literalists that I know is that I tend to see fewer things that need to be taken literally and/or historically. I think most people think context has something to do with biblical interpretation (I hope we all do) it's just that I see many more places where the context itself merits a more metaphorical, less literal understanding of the text. We have to consider that before the enlightenment history and fact were seen very differently than we see them today. Just that makes a difference because the context of scripture is a pre-enlightenment world which often may have resorted to myth before science and parable before history in order to interpret their reality and understand God and the world.
Take the classic example of Genesis 1 and 2. In our context it might make sense to take it literally because the whens and hows and how-longs of creation are important to us. But were those questions important to the original author and readers? Probably not. So in the original context a literal reading of the creation poem, concluding in seven-day creation, was not necessary. What was more necessary was to see the sovereignty of God, the otherness of God, and the purity of the original creation in their story. It was important for their story to stand in contrast to the other creation stories they were hearing which basically saw the world as tainted from the beginning by, for example, the blood of an evil goddess (Tiamat in the Enuma Elish) and which basically saw the gods as angry, manipulable, and always fighting. It was important for them to highlight that the world was good and that it was created by a sovereign monotheistic God, the same God who freed them from Egypt and will one day restore the world to right. The creation story's function in the greater biblical narrative is to stand as a foundation to which we can look to and upon which we can build and understand our eschatological imagination and our future hope. Eden is the cornerstone of God's great plan for the world. That narrative function is not in need of seven-day creation or, for that matter, of any answers as to how or how long the earth was created beyond the simple proclamation that the God of Israel created the world.
We need not force scripture to ask or to answer questions that it never meant to answer, perhaps those questions belong to the theologian rather than the biblical scholar. Many stories in the Bible, as with the creation narratives, answer the questions at hand and serve their function in the greater narrative despite their "historical accuracy" and despite whether or not we should take them literally (though, I will say, some stories probably need to be taken literally or read historically for them to serve their narrative function). There is often no reason to say the story couldn't have happened historically the way the bible says it did but at the same time there is no reason to fight to the death over that discussion. If the historicity of a particular text makes or breaks your faith, perhaps you've missed the point.