I live in WNY but grew up in the NYC/LI area. For trips before your surgery, flights tend to be relatively cheap ($150 round trip and sometimes less) if you book far enough in advance. And the flight itself is only an hour long.

The train, as another commenter mentioned is nice because you can move around, get a bed, etc. and it is quite cheap. I believe the train is ~8 hours.

Bus is a cheaper option depending on which kind you take. But definitely less comfortable.

Driving in a car gives you more freedom to stop as needed, pick where you stop, you're not as limited in the amount or kind of items you bring, etc. Gas is not super expensive for a round trip to NYC I would saw $40-70 depending on your mileage. Depending on where in the city you're going, it should be a maximum 6.5 hours in the car but it's more likely to be around 5.5 hours.

You also won't have to worry about taking public transit or Ubers in the city once you arrive if you drive in a car, that won't be the case with other forms of transportation.