Trailflix entry is here
Trailflix quotes 60km, but that would include the road section between Wentworth Falls Station and the former Queen Victoria Memorial Hospital. In fact, if you park at QVH, you get almost exactly 40km of trail riding, including three category 5 climbs. It also allows 4-6 hours, but I did the 40km of off-road in 2 3/4 hours including breaks without too much trouble (despite a painful knee issue that resurfaced partway along), and I don't imagine the road section adding more than maybe 45 mins to that.
Drive along the Great Western Highway to Wentworth Falls and turn off at the Pot Shop. Follow Tableland Road to the end of the tarmac, at the QVH. From here, the trail heads off as a continuation of Tableland Road. (This access is also good for Anderson's Firetrail
Route-finding is as easy as can be, just follow the road till you reach the end. On the way, you'll see Battleship Tops, and pass some private residences (don't trespass or otherwise be obstructive) and mostly head downhill, with an overall elevation change of about 200m. You'll climb 324m on the round trip, via three category 5 climbs. The views along the way are somewhat restricted, but at the end a sweeping vista of Lake Burragorang (more familiarly known as the Warragamba Dam) can be had from McMahon's Lookout.
Like all Blue Mountains routes, the surface gets sandy and sticky in the wet, so can be wearing on components. Disc brakes are recommended for this reason.
Overall, not by any means as good as some other rides, especially as it's just graded trail which is accessible by 4WD and AWD for its entire length, but a decent distance and quite a nice view at the end, and some of the downhills are very nice indeed - just remember you're sharing the road with vehicles.