Do not got caught in the old paradigm.
During the cold war, political theory very much spun off of game theory.
That put emphasis on the single left-right conception, and ignoring those farther left or right than the bulk of the parties under the idea that they have to side with their parties.
That is broken. #GenZ and #Millennials reject that. If a candidate violates their key principles, they won't vote.
Politics has changed on the right and on the left.
That is actually a tried and true strategy. You campaign in a state to get "turnout" in larger population areas. It's a waste to try for "converts" this late in the game. People in swing counties may vote in their districts, but they can and do travel into the cities for rallies to get "excited".
It's not smart to try and visit county by county. Winning is done by the state. Maybe in one of the two states that proportion their electoral votes, but PA, as every other swing state and nearly all of the US... Winning by a huge margin in the cities, wins the whole state. It's a better tactic than what you're suggesting.