Heads up on Hartshorne and ferry access from NYC?

I can't vouch for those trails, but since the highest spot in that area is a 266 foot "mountain," I can't imagine it's as fun as some of the riding that Northern NJ and Westchester County have to offer. Check out rvccmtb.com for information on Ringwood State Park (you can get there via NJ Transit trains from Penn Station or via the PATH train to NJ Transit out of Hoboken). Also check out wmba.org for information on the three big Westchester County mountain biking areas- Blue Mountain, Graham Hills and Sprain Ridge park. There are public transport routes to each (Graham Hills being the easiest- a 1 mile ride from the train to the park), and all you need is a $5 lifetime bike pass from the MTA plus a round trip ticket. Check out the MTA and NJ Transit websites for their bike rules.