I see that you already have Niagara Falls on your list. I would suggest the Frank Lloyd Wright house in Buffalo. Buffalo has some of the best historic architecture in the state. Ellicott Square Building, Guarantee Buildng, St Paul's and St Joseph's and Our Lady of Victory Basilicas. The Kodak Mesuem in Rochester and Abbey of the Genesee just south of Rochester, Thousand Islands and the Castle, St Laurence Seaway Locks. Guess you can tell that i think that New York State has a lot to offer tourists. Have a safe trip.