I walked some of it today, 11/8/09. The entrance by Jones Point is very overgrown. Beware of ticks! Once you get past that, the surface is alternately good enough to mountain bike on to challenging. It gets wider soon enough but I didn't make it to the end so I don't know what the northern half is like. Good views through the trees of the Hudson and Westchester hills.
I don't think Old Ayers Rd (how you get to the southern end) is marked from 202/9W but there are some signs at the turnoff. I know there is a Dead End sign. I missed the turn, going north, the first time. The northern end might be easier to see as the gate is visible from the 202/9W.
Iona Island, north of the trail, is tempting but since it is a wildlife sanctuary, you shouldn't go past the railroad tracks, and it's probably not a good idea to ride along the tracks either. Still, it is a nice* marsh with good views of the mountains behind you. (*Nice in the sense that it is big marsh but it will smell and you'll see pollution all around, though not much litter, thankfully.)
Nice Destination; Mediocre Trail Surface
"As the posted trail description indicates, the Jones Point Path is a route bicyclists bound to and from the Bear Mountain Bridge can use to avoid a very dangerous segment of US Route 9W. The trail gets limited use by bicyclists though, because most of those cycling along US Route 9W ride road bikes with narrow tires and this trail is not paved.
The fine ballast surface is ideally suited for foot traffic and bikes with wider tires, although trail users should expect to encounter frequent ruts created by heavy water run-off from a nearby mountain range. However, the dedicated trail user road shoulder parking area along US Route 9W is nicely paved and large enough to accommodate several vehicles.
During months when foliage is at its peak, this is a very shady route providing limited vistas. In late fall, winter and early spring, trail users can catch glimpses of the Hudson River, Bear Mountain Bridge, and nearby Iona Island’s Nature Preserve.
The southern trailhead provides access to the quiet hamlet of Jones Point. Here trail users can walk to the Hudson River’s west bank, where they may then fish or picnic in several spots. An added plus for train buffs is that CSX Corporation’s River Line runs right through Jones Point, 56 freight trains during every 24 hour period. And if that isn’t enough, Metro North’s Hudson Division passenger service operates on the opposite river bank and is clearly visible from Jones Point!
This isn’t the best trail I’ve been to by far, but one that I’m glad I went to at least once.