Funny how the Bible, well documented and verified, is given less credibility than other ancient documents and events that have far less to back them up.
How about this approach:
There are people in modern times who claim to have seen and spoken to Jesus. Would they be reliable witnesesses? Didn't Oral Roberts claim to have seen Jesus? I'm sure there are others.
My point is how could the atheist challenge someone's claim that "I saw and spoke to Jesus on Wednesday 2:00 PM." Unless the atheist could prove the witness was somewhere else on Wednesday at 2:00 PM, how could he impeach his testimony? (Provided the witness was otherwise honest and reliable).
Biblical manuscripts are the oldest of all ancient documents, with few exceptions. That is why the Dead Sea documents caused such a sensation.