Hi, Alan,
So, why are you going backwards, anyway?
Let us know if you slept in the 3 Cantos albergue. I hope your Camino is off to a good start, in spite of this.
I'll just echo your caution about not getting too caught up in this "ask the locals" mindset. Obviously, in some places it's essential to rely on people who know what they are talking about, like the pilgrims office in SJPP, which has up to date weather information on the crossing to Roncesvalles. But in many instances, I have met peregrinos who followed the locals' advice (which is usually to stay on the side of the highway and avoid the Camino) and as a result missed some beautiful, perfectly passable parts of the Camino.
This happens frequently on the Primitivo (where the owner of the bar in Paradavella seems to always tell pilgrims to avoid the Camino if there's been a drop of rain in the past day or so, and if you do that you miss a WONDERFUL walk); or on the Sanabres (where locals may tell you to avoid the path up to Albergaria if it's been raining, when in actuality that path is almost entirely a wide logging road, not a green tunnel with torrents of rain channeled down and much safer than staying on the highway), etc. It also happened to me just last summer on the Levante, leaving Medina del Campo when a well-intentioned "local" told us to stay on the road just because the camino would take us off into the fields and we would get lost. We ignored his advice and had a LOVELY walk.
So in many, if not most instances, my experience is that the locals are generally totally unfamiliar with the Camino and have never walked a step of it. They will almost always tell you that the best way to get from Point A to Point B is to stay on the side of the road because it's a shorter distance and a hard surface. My advice is to give the camino a try -- you can always backtrack if need be, but you can be sure that the off-road option is going to be prettier, more peaceful, and much easier on your feet.
Sorry to get off point here, but since you'll be in Arevalo, maybe you'll hit this section of the Levante. Buen camino, Laurie