What's the best way to get from North Salem to New York City?

Yes, the Harlem Line of Metro North has stops in the hamlets of Croton Falls and Purdy's plus the much larger station just to the South in Goldens Bridge where you can contact Metro North for parking availability with some daily spaces. Yet North Salem is very close to Interstate 684 which also then feeds into the Saw Mill River Parkway! Not as remote as people would think!

Probably Metro North, though if Queens or the Bronx is your destination driving will be a quicker choice. Unless you're going to one of the baseball stadiums- then I would DEFINITELY use the train!