I'd see McCain or Huckabee winning more likely in this scenrio over Rudy but I digress and apologize.
This scenario would depend on the economy and Iraq. If Kerry does a decent job with Iraq, gets some things done, and stops the economy from being as bad he could win, but if things go the same as in RL Rudy would win easily.
Kerry would also be hurt by Edward's scandal. He'd be gone more than likely and replaced. I'd see Obama getting it if Kerry is in rough shape to appeal to the base. In a better situation it'd be Barry or Biden.
Going with the RL 08 scenario Rudy should roll. Rudy would appeal on a theme of hope and Americana while focusing hard on solid improvement on foreign policy, the economy, and morals in government ala 2000. To that end I see Huckabee getting the VP slot. He gets the moral and religious base excited with his religous background and adds some populism to the Rep campaign. Rudy goes on his 9/11 background and has solid help from McCain. Kerry seems bored and doesn't excite as many people and Obama has to do double duty.
I see maybe a third partier but nothing major. Maybe Paul as a Libertarian. In 2012 I could see a Trump run of some sort possibly.
Anyways on Election Day in a RL type situation I see Rudy and Huckabee winning a solid win over Kerry and Obama. Obama helps to save the dems somewhat and is the favorite for 2012. Paul does great with his base and gets a lot of online voters and has a good showing for the Libs at 3%
Rudy/Huckabee- 321 EV's
Kerry/Obama- 217 EV's
That's the best I see Rudy doing. The Reps would do much better in Congress with crushing pickups in both houses.