The answer is probably complicated. Game theoretically, they’ll pay attention[0] to the places where their campaigning has the biggest marginal impact, but that doesn’t immediately tell us much.

That will make big urban areas appealing. However, if you think there are diminishing returns, it should cause them to spread that attention more, avoiding the last month where they repeatedly visit the same state over and over again.

[0] This might or might mean visiting those states.