1. Everything she said is true, even though not one person she claims could corroborate her story can do so. Nobody she claims was there, has any idea what she is talking about, even her best friend.
But she is still telling the truth.
2. She unconsciously "dreamed" the entire incident and can't tell reality from that dream. That explains how she would remember specific details, as they were the details actually in the dream. She does not remember how she got to the party or where it was or how she got home because that was not in the dream.
3. As a good campus liberal, she was attempting to submarine the nomination by making up and giving a confidential story. She just wanted to raise doubt in the committee. The dems knew the story was weak and did not even present it to the committee. But later those same dems determined that they could manipulate the media and get their easily manipulated constituents into the streets by leaking the story. After after the dems leaked her story it got out of hand.
Added (1). I think that the body of evidence makes number 1 unlikely.
I think that as you combine this with the lies about "two exits" from the house story (where she actually was running a business with a separate entrance) and the "I'm afraid to fly" story, where she flies on vacation often, this starts to skew toward dishonesty and toward number 3.