We hiked it in late August. Messaged Jazzbo about the route after his post in July/Aug. Using just the AMC map (but did look at Google maps), we drove in with a beemer all the way to the first wash-out w/o loosing any pieces. Very easy drive. Here's the route from my notes:
On Rt 142, E Madrid Rd sign is across Rt 142. Also a sign for Manzer Hot Mix plant.
2.9 miles. Black top ends. Ready-for-blacktop quality gravel begins.
4.7 miles. Road ends at a bucolic setting. Take a hard 90 degree L ~ 10 yards after the farmhouse (no go straight). This is on AMC map at E, Madrid. Road is now rougher gravel.
5.3 miles. Turn R onto Barnjum Rd (sign). Chicken farm on R (last house?) The turn, but not the name of road, is on AMC map. Road gets somewhat rougher.
6.3 miles. Curious stone table on L.
I have a hard time matching notes / milage at this point, but follow the main part of road. A branch to R (do not take), and a few pull-ins for camper spots along the road - most being used that day.
9.3 miles(?). Road comes to a very large distinctive clearing and seems to bear L. Go straight. Not on the AMC map.
9.6 miles. First wash-out. Might be able to get past, but we parked in a pull-over spot and walked.
16 minute walk up the gravel road to the AT (1 mile?). No sign, but an obvious 'hole in the woods' with a white blaze not far up the trail.
If you can find Jazzbo's post, he has great pix of the wash-outs.
Have fun!