UGH!
That really sucks. RIP
I did the Hudson Corridor about a year ago, motivated in part by the possibility of just such an occurrence resulting in additonal regulations or even closure of the route. It's tight in there, but probably a lot easier than flying into Oshkosh. You want to do it on a really good day, when you are on top of your game and you feel like you have eyeballs out your a**. I set the first notch of flaps and flew most of the way at 70 knots with the windows open. So glad I did it. I feel sick about the nine souls lost.
I started at the north end: the Tappan Zee bridge where you should be heading for less than 1000 feet.

Keep right after the George Washington Bridge and less than 1000 feet

I made three loops around "the Lady" broadcasting and listening to the tour helicopters. You gotta be BELOW 500 feet here to slide under a shelf of the Newark control zone if you go west of the statue.

It would be a crying shame if we were to lose the freedom to do this:

Heading back north, not many options to land out. The Intrepid looked like a good spot for a Maule:

Terrain warning is just about useless too:

Apologies to all for using up so much bandwidth, but it was a beautiful experience.
YB