I think you're right, but Rudy will stay in the race until Fred wraps it up. I think he'll cut a deal for Attorney General or Homeland Security director in exchange for endorsing him and campaigning for him in blue states and other areas where he's popular.
It's the same thing I believe Newt is really aiming for with this "Will he or won't he?" he's been doing. Waiting for September to announce, there's no way he'll ever raise the money he'll need for Super Duper Tuesday. But he probably already knows that and wants a cabinet spot.
Duncan Hunter for Defense Secretary? :-)