Will be fine except for the fact that NY has no escalators.
In the deeper subway stations, there certainly are escalators. You don't spend much time taking subways to come up with a statement like that. Mine has a set of escalators at both ends of the platform.
The subway is ancient an of such incredibly poor comfort (they really need to upgrade it.
Where is your local 24 hour subway system? Have you been on the new R160s which are used on the E, F, M, J, N, and Q trains. What about the new R143 on the L? The new R142 on the 2, 4, 5 or 6? Crowds are there during rush hour but the subway is MUCH better than it used to be.
A true embarrassment that no dedicated airport train exists from the main stations.
What are the "main stations"?
The embarrassment belongs to you.