Concerning Noah's ark, it is obvious to me that the Bible is suggesting that God directly intervened to save Noah and his family. If they were saved by God, why is it so hard to believe that He performed a miracle to save the animals too. This of course is NOT science or history in the classical sense, this is faith. Faith is evidence for things not seen. If you do not accept the assumptions of the Bible, don't believe in the story of the Flood, but don't believe that you are immune from making assumptions. You WILL believe in something which cannot be proven any more than the assumptions of the Bible writers. Those beliefs will rule your life.
The advantage that true Christians have is that they have hope. They have unprovable assumptions, just like you, they have evidence, just like you, but they have hope in Someone who loved them so much that He gave His Son that they might have eternal life. Crazy? No more crazy than any other worldview, and it can be quite consistant, and not a bad life altogether. If in the end, my assumptions are wrong, then I'm in good company, and I haven't lost anything. But, if I'm right, my reward is eternal.