Ford's moderate appeal kept him closer up north. However, a 16 pt margin in MA isn't exactly tight. McCarthy's showing probably saved Ford in IA, ME and a few other tight states.
Keep in mind, Ford's charge starting in Oct was almost enough to steal the election. Two more weeks and Ford may have won. Carter did just enough to hold OH, PA and got the "halo" effect in WI from Mondale.
Running mates and neighboring states both have effects that are nebulous at best. I seriously doubt that Carter won Wisconsin because his running mate was from a neighboring state.
