It is all fine and good to look behind the layers of Christian interpretation of Paul and Paul's interpretation of Genesis, but what do we take for life from all of it today. One benefit of analyzing the layers is the potential clarity it brings on what exactly we are believing. We now have some choices to make and a much more complex landscape to find ourselves in.
Contemporary culture brings other factors to consider in our picture as well. For example, it is virtually the unanimous consensus of scientists across the disciplines that the universe is very, very old and that complex life evolved over time from simpler forms of life. We know the dirty word, "evolution." Could virtually the entire scientific community be wrong? Certainly they seem to have been before--on whether the sun goes round the earth, on whether time was a fixed framework, on whether space was continuous and infinite. But still, when we realize how much more there is to Paul and Genesis than we might have thought, one has to wonder whether we have as firm a biblical basis as we might think to oppose the notion that God might have directed an evolutionary process in some way ("theistic" evolution).
If we want to be able to engage our culture, we had better think long and hard about the options before we simply close down discussion and just say, "No matter what evidence you see, you will lose your faith unless you close your mind to it." For example, I cannot think of anything that would contradict the authority or truthfulness of Genesis 1 if it were a poetic presentation of God as sole creator of an orderly world rather than a straightforward blow-by-blow documentary.  Indeed, those who think they take Genesis 1 literally somehow miss that God places the sun and moon on Day 4 in the expanse that has waters above it. In other words, if we had to take Genesis 1 literally, we would have to believe that we go straight up through sun and stars to primordial waters at the top of creation. 
If anything, Romans 5 and 1 Corinthians 15 pose the greater challenge, as Paul seems to say that death and the decay of the world entered as a result of Adam's sin. At this point, some Christian scientists, convinced by the evidence of their field as they understand it, will strategize possible reinterpretations of Paul. Perhaps he meant spiritual death entered through Adam, not physical death. Perhaps he actually understood it as Genesis does--that everything would have died anyway and it was only the fact that Adam and Eve did not get to eat from the tree of life that resulted in death.
Another thing to keep in mind is that we as Christians regularly shift over time in what passages we emphasize and do not emphasize, usually without realizing it. For example, at one point in my life, passages in the Bible against women adorning themselves with jewelry caught my attention (e.g., 1 Pet. 3). An earring was such a big deal to me, given where I was raised, it seemed impossible that a woman could wear one without it being a big deal. I now laugh about that, knowing that most women are about as "prideful" to wear an earring as I might be when I try to match my shirt and pants.
Whether we should focus so hard on such a specific reading of this handful of 5-10 verses is a legitimate question, especially since the arguments of the Bible are always made in the categories of their original authors and audiences--otherwise God would not have got his message across. Paul's point, is it not, is that Christ has abolished death for all those who trust in him. To make this point, he draws on one contemporary understanding of Genesis. His point has to do with the Romans more than with history and certainly more than it has to do with science. Here we remember that it was atheistic evolution and its social consequences that got the dander up of fundamentalists in the early twentieth century.  Before then, many godly Christians had tried to strategize whether some form of theistic evolution might be compatible with the Bible and Christianity, as many godly Christian scientists do today.
So let those Christian scientists who are competent debate the evidence both for and against theistic evolution. Let us remember that science is often wrong and has been known to change its mind many times on a massive scale. But let us also remember that the biblical texts themselves are not without their own ambiguity, and that the Spirit has often "instructed," "corrected," and "trained in righteousness" through figurative interpretations.  What will only hinder faith in the long run is if we pretend we have it all sorted out and that everyone who disagrees with us is an infidel--especially when most of us are neither competent scientists or interpreters of the Bible!
 In other words, if it were more in dialog with the other creation stories of its day than with the concerns of the twentieth century.
 Not to mention the likelihood that Genesis 1 had a flat earth in mind.
 For example, it was ironically social Darwinism that fueled William Jennings Bryan's opposition to evolution. Social Darwinism was an attitude of "survival of the fittest" among the elite and rich entrepeneurs that was used to justify a complete disregard for the people they emploited, especially their helpless workers.
 See volume 1.