Acts 12:12 'John, also called Mark'
Acts 12:25 'John, also called Mark'
Acts 13:13 'John' Since no other John went on the missionary journey with them it would have to have been 'John, also called Mark'.
Acts 15:36-41 'John, also called Mark', 'Mark'
Colossians 4:10 'Mark, cousin of Barnabas'
It is hard to tell that the Mark in 2 Timothy 4:11 is actually John Mark but there is one clue. Paul says 'he is helpful to me in my ministry.' Since Paul went on his first missionary journey with John Mark (Acts 12, 13) and since he was in jail with John Mark when writing Colossians (4:10) also Philemon (1:24), then Paul would have known that John Mark was helpful, and since no other Mark was described in any of his missionary journies, it's safe to say that John Mark was the one which Paul spoke of in 2 Timothy 4:11.
When Paul wrote Colossians he was in the Roman jail, and it says Mark was with him. In 2 Timothy, Paul was in a Roman prisonment, in chains, and he asks for Timothy and Mark to go see him. It is a good guess as to say that Timothy and Mark both went there, this gives alot of evidence to the fact the Mark could have been in Rome. When Peter writes 1 Peter, he is in Rome, saying that his 'son' Mark sends his greetings. Coincidence again? Hardly.
Clements of Alexandria, Papias, and Origen are not indirect sources and therefore is not hearsay.
And finally, how is that not substancial evidence that the authors name was Mark?
PS. Please read info given (ei. Biblical texts) before making a statement. I had to give you useless information the Acts qoutes as well as Colossians that you could have got yourself if you read them. Thank you.