I have walked from Ponferrada to El Acebo (NOt backwards on the Francés, but on a beautiful trail called Puentes de Malpaso) to Peñalba de Santiago and back to Ponferrada. Details
here. I had intended to walk from Peñalba de Santiago to Las Médulas a few years ago, but I had a GPS meltdown. When I got to Peñalba, I couldn’t pull up any tracks from there to Médulas, and I was reluctant to go without GPS, so I hitch-hiked back to Ponferrada and started the Invierno from there.
There used to be a wonderful private albergue in Peñalba, La Masera, where we stayed when we walked the circle. That place has closed however, very sadly. I don’t know of any place to stay in Peñalba, though some reported that one of the bars found them a bed. There are pricey multi-night-minimum places on vrbo or airbnb.
For those wanting to visit Peñalba off the Francés, it’s a very nice walk from Ponferrada. No public transport, but if you go in season, the odds are very high that there will be someone there who is visiting with a car and who will take you back to Ponferrada. If you take the tour of the church, or speak with the “locals” who are sitting around outside and eager to talk, they will help you.
For those who want to walk from Ponferrada - Peñalba-Médulas, the problem isn’t the route, because there are good tracks. The problem is the lodging in Peñalba or San Pedro de Montes. I can’t find anything, but maybe someone with better sleuthing skills will be successful.