UniChris

In terms of ride ideas rather than meetups, going further into NJ there's the D&R Canal towpath, it's unpaved but I'd guess you'd be okay on 32s. Nearest part is between New Brunswick and Princeton but there's a further part northwest into PA from Trenton.

Making your way back via NY on roads you could do the Bear Mountain ride up the west side of the Hudson and back starting from the NJ side of the GWB (also through the park at water level under the bridge - no personal experience, but everyone talks about it). Avoiding that you could do the South County / North County / Putnam trail up the middle of Westchester (a little bumpy in spots though). If you pass through CT the Farmington Canal trail bisects the state north from New Haven up to Westfield MA is really nice, also the Airline Trail is an (apparently easy) gravel ride many people say great things about that I'm yet to see.

NYC itself is probably worth skipping, the Hudson River greenway can be scenic but it keeps growing new aggravations. (And they really mean those traffic lights...) . Still, you can probably get on the PATH train from jersey city or wherever (or an NJ transit heavy rail trail) with your bike on a weekend and see a bit of NYC riding up the river and back down. With a small light it's fine (and well used) after dark, too.