Mark
I walked this way last October and my experience was much better than the one cote has recorded. There were definitely good yellow arrows from Touginha - I even photographed them.
Before then, there's nothing to worry about in my view. If you go to the tourist office the evening before in Vila (very interesting town with bizarre Aquaduct), they'll give you a basic map and draw the route for you.
I did a little detour to follow the river and wasn't sure I'd got back on the right road. I then had a wonderful experience like being in the movie The Truman Show. I paused at a small road and a woman opened the blind on her window and pointed left. I hesitated a second at the next small turning and an old woman on the other side of the road putting her rubbish in a wheelie bin stopped to indicate I should go straight on. Then I got to a junction with shops, turned right and slowed to look for a road sign that correlated with my map. A man free-wheeled his bike up to me and explained in English the next stages of the route, which pretty much brought me to the first yellow arrow.
I have a theory that they don't want yellow arrows here, as they enjoy being able to help pilgrims find the way....