Ask him whether he keeps it on a tender and if he's ever had any charging issues. Look on the left and right side of the frame where the shift and brake levers are, if you see any marks on the frame it's been down because the levers get jammed into the frame when it hits the ground. Other than that, check for general maintenance and stuff. Ohlins suspension should feel nice, just check to make sure the seals aren't leaking. Also, expect it to be hard to find neutral while the bike is running, all Milles have this issue. There's nothing wrong with the trans or clutch. The best way to find neutral is go to second and tap down lightly while the bike is moving, or if stopped tap down continuously and it will pop in to neutral. That's about all I can think of for now. Good luck! I'd kill to have that Haga rep.