Mrs BWW and I walked the Merrick from Loch Trool a few years ago. It was a great walk, only a day circular and the first time but we were fortunate to find the Grey Man.
A local lady pointed out an area north west, it had some very interesting geology apparently. But it was a bit too far too include in our day.
The return from the Grey man was not too difficult, we found a trail over the Rig of Loch Enoch ridge and fortunately kept to a high contour around the Murder Hole, skirted around the eastern flank of Meaul keeping high for as long as possible, before joining the track back to Gairland Burn.
Seemed to work pretty good, probably a lot wetter than this year.