I got from the question that she is asking "if there is a shoulder do tourer ride them instead of on the road lane".

Now I have only done a few overnight trips, but if there is a shoulder and it free and clear of debris and there is traffic I will ride on it. The roads that I ride on are pretty much chip sealed. Chip Sealed is where they build a dirt road, and then they put tar/oil down and put rock on it. So the roads are rough to ride on when they are new/newer and if they are not used a lot. I tend to ride alot in the groove where the right tire is on the road. If there is a shoulder and its a chip sealed road, I will stay in the grove because it tends to take a lot more energy to ride on the shoulder than in the groove. I will move over to the shoulder if a car is approaching and there is not another lane. If I am a on road that they use asphalt on, I will stay on the shoulder.
So for me, it depends on the type of road it is and the age of the road.