Romney will win early in the more liberal states that rarely vote for a Pub in the general election. Perry will emerge in the states that represent the core of America and the Pub party. It will be Perry if the Rat crossover vote isn't a factor.
One thing that people haven’t noticed is the number of incumbents in Southern states who have endorsed Perry. Something like 140 officholders in GA just endosrsed him in about a week ago. Don’t underestimate the value that will have in putting together on the ground campaigns in as you say, the states Republicans win in November.