Yes, there is a difference between the two. The first one: "I was to New York" does not have the logic, rather you have to say "I went to New York" The second: "I was in New York" means you were in New York some time in the past, and the first means the same. If in case you you were confuse using "to" here are some informations: "To" as infinitive; [To + Verb] e.g. to read, to eat "To" in prepositional phrase; [To + Noun or Pronoun] e.g. to them, to a friend

That's not a silly question. 'I was to New York' does not make sense in English. 'I was in NY' = I was in the city of NY at some moment in the past. You could use 'to NY' as part of an action - 'I went/am going/will go to NY', or 'I look to NY for inspiration'