My wife's uncle finally replied (guess he thinks his newspaper career's more important than me ;-)).
The odds on bet, says he, is that Sen. Corzine runs, if only to prevent your state Senate president (name escapes me) from running, as the party bosses feel more secure with Corzine. They've also figured out that they stand to get a colossal PR black eye if McGreevey is allowed to stay on and there is no election (they needed to study that?).
This way, they assume that the governor's seat (and thus Corzine's Senate seat) is safely theirs. They can't think of any Republican who'd run except maybe Bret Schundler, who they figure they can again successfully tar with the "extremist" brush.
Of course, should someone persuade Steve Forbes to run, all bets are off. Forbes, after all can self-finance even better than Corzine, as he has lots more money.
My thought is that the Republicans could score more than a few points by making a new logo for the state designed to resemble a certain Texas corporation's and making ads around it; you know, "Welcome to NJRon"?