My understanding from reading posts in the Touring subforum is that NY Bike Route 17 has a lot of traffic in places.

As for the canal path, it's been 15 years since I rode it east from Lockport to a little east of Rochester, but IIRC, there are often parallel roads you can take if you don't like the surface.

If you have the time (and a passport), I recommend taking the Peace Bridge from Buffalo into Ontario and riding up the path along the river to Niagara Falls. The Rainbow Hostal in the old section of the city was a nice place to stay. From there, you can cross back into the U.S. and get to Lockport pretty easily. That segement in on Adventure Cycling's Northern Tier route. You could order the map and have it sent to you via General Delivery Mail. if you cannot figure out the route yourself.

If you are heading up to the Monroeville, IN area, note that there is a great community center there where cyclists can stay for free assuming it's not being used for something like a wedding. Real nice place with showers and, more importantly, a.c. That's also on AC's Northern Tier route. Maps 9 and 10 of the Northern Tier route would get you from Monroeville through Rochester via Niagara Falls, ONT and the Eire Canal Path:

Northern Tier | Adventure Cycling Route Network | Adventure Cycling Association

When I was in Monroeville in '99 there was a yellow stripe painted on some street(s) that led you to the house of the guy who has the key to the place. If that's no longer the case, ask around in town and I am sure you can get the necessary information. It's not a big town.

How are you planning to enter NYC? The only way to actually ride in from the west is the G.W. Bridge.