A cautionary tale... How NOT to do the Southern Upland Way... as told to me in a B&B at Dalry:
Some guy once drove his car to Portpatrick and, having the afternoon to spare, decided he might as well start walking the SUW to Stranraer. When he got there he found a place to stay, then got a bus back to Portpatrick, picked up his car and drove it back to Stranraer.
The next day he walked from Stranraer to New Luce and found a place to stay. He asked about buses to Stranraer so that he could pick up his car, and was told there weren't any. Undaunted, he set off to hitch-hike to Stranraer and it took him ages, so that eventually he drove back to New Luce in the dark.
Day three saw this guy walking to Bargrennan, where he booked into the hotel. Again, he discovered that there were no buses between Bargrennan and New Luce, so he had to hitch-hike back for his car. It rained, and it got dark before he completed the journey, and he was very late getting back to Bargrennan.
Day four, and a 24 mile walk from Bargrennan to Dalry, where he booked into a B&B (staying with the folks who told me this story). Buses from Dalry to Bargrennan? Of course not! Driven half-mad by walking, blisters, more walking and hitch-hiking well into the night to keep getting his car, the guy was almost in tears and begged the B&B folks to take him to Bargrennan so that he could collect his car. With judicious use of maps, they explained how he was walking west to east, but how all the roads in the area ran north to south, and how a 24 mile walk for him was a couple of hundred miles return journey in a car!
By now, dear reader, you may be wondering why this guy was so attached to his car. Simple - he was taking the car across country so that he could drive home from Cockburnspath!
I doubt he ever made it... there were no more stories of him beyond Dalry.