When deciding which route to take to climb Slieve Donard, many routes had an out-and-back aspect to them, whereas Mountaineering Ireland's Irish Peaks book features a looped route without any repeated sections. The route also includes the spectacular Chimney Rock Mountain which has the remains of a significant quarry and its machinery and rail line.
The Bloody Bridge carpark just south of Newcastle has parking for about 25 cars and also has well kept public toilets. The walk starts along a popular and well-marked trail towards the Mourne Wall.

Leave the Brandy Pad trail at the quarry heap, turning sharply left and then climb along the abandoned rail line to the old quarry face. Just beyond the quarry face, turn right and scramble a little until you find the trail to the summit of Chimney Rock.

As you approach the summit of Chimney Rock Mountain, you'll have spectacular views of Slieve Donard to the nortwest and Slieve Commedagh beyond it, and of the Isle of Man to the East.

Looking South from the summit of Chimney Rock Mountain. From the summit follow the ridge northwest until you reach the Mourne Wall where it meets the Brandy Pad.

From the South of Slieve Donard looking up along the Mourne wall. This is not the route proposed for conservation reasons. Instead, you should contour around to the west to the col between Donard and Commedagh. Crossing this wall at the stile, climb the stone path to the summit of Donard.

Descending from Slieve Donard to the north east to the cairns on Millstone Mountain. From Millstone, turn south and follow the ridge back to the Brandy Pad trail. This return path was quite a challenging descent across steep rocky terrain. The river crossing to rejoin the Brandy Pad was precarious and not for the fain-hearted. Its not a descent route that I would recommend except to the hardiest adventurers.
All in all, it was a very challenging walk and a wonderful experience on the clear bright day that we had.