I found the interview interesting as I've always been interested in this subject. Understanding always it's his opinion as a historian, which influences his observations perhaps to his own desired outcome.
Fresh Air podcast: Bart Ehrman's new book "Triumph of Christianity"
I've always enjoyed reading Ehrman, I find him very persuasive. I'll have to look for this book.
LOL - I wonder if he will verify the WT's assertions that the earliest disciples walked around "door to door" carrying scrolls of scripture?