Is there still a viable inside waterway thru New Jersey?
There is, from Manasquan south to Cape May. But it is shallow and windey, so it is slow. If you can possibly do the outside, I would.
On that note, the only weather you have to worry about is when the wind is blowing with an easterly component or SSW and even then I would do it with 15 kts rather than struggle inside. If the wind is out of the SW, W, or NW stay close to shore and 20 kts is no problem.
David