Oooooh, it appears I touched a nerve!
Why don't you compare Bush's stops in the last couple of weeks in 2004 with your list? And compare McCain's schedule with Obama's schedule? Have you noticed how every time Obama goes somewhere Palin or McCain is there the next day, or a day after that? For example, Obama to Des Moines, Sarah to Dubuque.
Then try this: What does Obama have to do? He has to hold EVERY BLUE STATE and take a red state. McCain's task is about defense. Hold the red states, take a blue only if it's a juicy oppportunity. Obama has to take a red state, so he's in all the states you listed trying to take one, and McCain's trying to keep them. Basically, if their positions were reversed, McCain would probably be in all the same states he's in now.
So there you go. BTW, PA was NOT in play in 2004, despite what the media was saying. Dubya lost it by more than he won Ohio. This time it's in play. That means something.
I think they go where their internals tell them they need to defend or where an opportunity lies....or they go somewhere to make the opponent spend money....not that big an issue this year for Obama admittedly
and it looks like Mccain is doing 9-1 defending and Obama is doing 9-1 attacking
PA is the one semi bright spot and if it fell for Mccain it would offset several red state losses