What's the cheapest, most direct way to get from Beijing to Taipei by train and ferry?

There is no direct train or ferry from Beijing to Taipei. To be honest, the best way is by air. You can pay attention to the arifare in real-time. The airfare changes oftenly and you may find a suitable discount ticket.

I know there is no direct flight, but I'm talking about most direct. Couldn't one save a lot of money by taking a train to Shenzen, then to Hong Kong, then ferry to Taiwan? I think there are options like that, but I wanted to see here if someone knows a faster way, and still not fly.