Any interest in a group run in the Palisades Interstate Park that runs along the top of the N.J. Palisades and along the Hudson river from Fort Lee north to the New York State line? Lot's of choices for route and distance.
Yes. The Long Path runs along the top of the Palisades. It's flat and less rocky in the south and a bit rolling and rockier in the north. The Shore Trail runs along the bottom along the Hudson and is mostly flat except for a section in the north called the Giant Stairs that is a mile long rock scramble. There are 6 or 7 trails and a couple roads that connect the two. The Forest Trail, for example, in the north is about 0.3 mile and rises 500 feet, the upper half is mostly stone stairs. At the very southern end Hudson Drive (a road) gradually descends. Other connecting trails in between vary in height/length and steepness. There are 3 main entry points with free parking and rest rooms: Allison Park in Englewood Cliffs, Park Headquarters in Alpine, and the State Line Lookout in Alpine (between Exits 2 & 3 off the Palisades Interstate Parkway (PIP)). At the State Line Lookout there are also a number of cross-country ski trails that connect to the Long Path. So there are a variety of ways to but together runs that are mostly flat, or have one ascent/descent, or two (or more, yikes), or even include the Giant Stairs section (or part of it), which is more like a 30 minute hike (the northern ascent/descent to this section is a bit treacherous, as parts of the trail have eroded away... it's better to enter from the south and go some part -- maybe all -- of the way and then turn around and do it again).