USB doesn't just adapt to ethernet. At best you'll need some converter, and in that case its going to be USB>Ethernet>USB. If you did that, it would probably be okay because you won't be affected by the really high latency times there's going to be.
Like, the reason I am considering this is at school there is ethernet plug-ins all over campus which is each to connect to my laptop, but the wifi setup is real crappy. And is a pain. And slow. I actually know the person who designed the pain in the ass login system for the college wifi, and he said he doesn't want to change it.