The non-existent "Romney Surge" in October made the Romney team think Pennsylvania could be put in play. Democrats said he was desperate like McCain in '08, while after the election it was revealed they were going for a blow-out, not a back-up.
They legitimately thought they could snatch Pennsylvania to get 305 EVs(they assumed they would win FL, VA, NC, IO, NH, CO, and OH), assuming uniform national swing.
He had a surge which fizzled in the last week.
Yes, his PA numbers were showing it reasonably close and closing. Turnout was also an issue. 2010 was also a GOP landslide in PA. Corbett, who I am not a big fan of, cleaned up across the state.