After you exit the final roundabout at Castle Douglas eastbound, you will be on a level section of road with two lanes Carlisle bound and one lane Stranraer bound.Approx half a mile later, these two lanes will taper in to one lane, and you will pass a junction with a road joining/leaving on your left. Slow-down here, because there is another road/lay-by (drive-through)on your left in about 200 yds., and this would be an ideal spot for you.This road/lay-by is very quiet, and about a quarter of a mile long. Hope this helps.