Can I "WALK" across the northern border from Russia into China? Can I get a VOA there?

I have a friend walking around the world. He is quite famous among adventurers. He is in Russia now going south, and wants to cross from Russia into China at the north near Mongolia. 1. Is this possible? Some say you cannot walk across. He has to walk specifically as he is making the longest unbroken footpath ever. 2. Can he get a VOA for this reason?