So long as the leaves are dry. I bombed down it a few weeks ago when it was covered with leaves. Only one or three turns where I had to touch the brake. A really peaceful climb up to the closed gate. Harriman was fantastic!
It's a fun descent. Occasionally I see guys on longboards going down that road. I was bombing it (on a bike) many moons ago (during a Tour de Cure ride, maybe 1992-ish?) and a fairly large butterfly (monarch? tiger swallowtail?) hit my chest. Even through my jersey that smarted a bit, good thing it didn't hit me in the face, that conceivably could have caused me to crash (I wasn't as experienced back then).
The only drawback to that descent is that it is such a pretty road that it is a shame to see it go by at a blur. Plus, the climb up the road to Lake Welch is tough, and boring, has more traffic and exposed to the sun. I nearly always go down Lake Welch drive and up Tiorati, rarely do I do it the other way.
Adding on the Arden Valley road/Kanawakee loop is always nice. Even the part on Route 17 isn't too bad, going south it is downhill and only takes about 10 - 15 min., and the shoulder is nice and wide).
It makes a long ride when starting from home, though. Kanawakee road from the circle to the Lake Welch back door is tough for me with that many miles and climbs in my legs, and even the relatively mild climb up Little Tor hurts.