It sounds like you are not even wanting Networking at all. It sounds like you are wanting to use the same device and just have different input types. Like if I were to connect 2 Xbox controllers to the computer how I would say player one controls this and player 2 controls that? However… if you are talking about having Networking and multi-user then that would be 2 separate issues. In that case you should first worry about getting the two inputs on one system working before venturing into Networking them.
I suggest you take a look at AppWarp for getting multiplayer networking in your Unity game. Its a cloud based solution without requiring you to host anything.
Here is the developer wiki where you will find a tutorial as well. Product Site