Sorry about your injury, but I'm afraid you are a lot limited, I made a shortlived attempt to train when I had a Bennett's fracture to my thumb, and it ended up not really being worth it, mind you it depends if you're in a full cast or not? As I was!!
All I done was try to keep below the chest up together and gradually get back into it when the plaster came off, that took a while mind, what with muscle seizure after six weeks!
You might have some more joy if you're able to incorperate some machine work, but not really a good bone to break though the scaphoid, not that there is a good one mind!