All you'd really need to do is stick some more knobby tires on it, maybe tinker with the suspension some and change the gearing.
But whats the challenge in that right?

The exhaust would have to be reworked as well, the fairing would have to go, and spoked wheels would need to be fitted at a minimum. If I were to get into all that, I'd rather scoop up a 650R engine and try to shoehorn it into something else.