Personally, I am certain that Noah's flood is a metaphor, for it would be flatly impossible for humanity to spread, multiply, and diversify to its present state from eight human beings 5,000 years ago. As a metaphor, we can understand that there was, in a manner of speaking, a "flood of unbelief," a time when only eight people out of all the world truly worshiped the God of Abraham.
I am certain that the story of Genesis is misunderstood, for how did the sons of Adam procreate? They left Adam and Eve and found wives in the land of Ur... which begs the question: where did those women come from? They certainly didn't come from Adam and Eve! Furthermore, how did the land of Ur get its name? To me, that implies that Ur was civilized enough at the time to have been given the name "Ur." Instead, I believe that Adam and Eve were not the first human beings, but the first people of God.
Then there's the 42 children slaughtered by a she-bear for mocking a prophet. Personally, I believe that this was merely a legend wrongly inserted in the Bible and Jeremiah verified (in the verse referenced above) that such did happen.
For those who truly wish to find salvation, they must first understand that they must hear the word of God preached by a minister who is sent to preach, as Romans 10:14-15 makes clear:
How, then, can they call on the one they have not believed in? And how can they believe in the one of whom they have not heard? And how can they hear without someone preaching to them? And how can they preach unless they are sent? As it is written, “How beautiful are the feet of those who bring good news!"
Those two verses make it obvious that one can't just read the Bible and believe — one must receive the preaching of the word (unless they have no opportunity to do so, and for such, Romans 2 would apply). Other verses in the Bible (it's in Timothy, I believe) make it clear that the preachers are to preach the same thing, saying, "Let there be no division among you." In other words, there's only one right set of beliefs and any church whose preachers tell us that those of other denominations will also be saved (several major Protestant denominations, for example) therefore cannot be the true Church.