Second update from the Vadiniense...
After walking up from Potes we arrived at the Monasterio Santo Toribio a little before things opened up. The very nice lady in the gift shop stored our packs while we walked around and had our chance to touch the true cross. As we were loading up and starting to head off afterward, she came running out to ask us back in to give us copies of the special Lebaniego certificate (like a compostela for making the pilgrimage there). Apparently they now have these.
In common with some others (at least as I've inferred from reading postings here), we also were confused by the "extra" yellow arrows after descending from Santo Toribio back to the highway. Instead of a straightforward and mostly level walk up the valley toward Espinama, we went up and down, up and down, eventually passing through Mogrovejo before descending again to the highway. Straightforward walking on and off the highway from there to Cosgaya. A little past there, we turned left off the highway to take a trail on the other side of the river. Watch out here. Pretty soon, the trail made a switchback up the hill to the left; don't go that way unless you are looking for a long walk. Instead, we stayed on the flat, following along the river, on an unmarked, very overgrown, but easy to follow path. We just kept on following it, trying to stay as close to the river as we could (almost always within sight or earshot). At Ilices we took the right fork: the trail headed up a steep climb for a bit, then descended very steeply before reaching Espinama. This was a longer day than we'd expected. A word of warning: overgrown trails and tall grass mean ticks. We pulled many small ones (about 1 mm diameter) off ourselves at the end of each stage with tall grass.
The day we walked over the hill from Fuente De to Portilla de la Reina was drizzling and totally socked in, with visibility only about 50 m. Good thing we'd had great views of the Picos on previous days. We had no trouble at all following the way. At the albergue in Portilla we met the only other pilgrim we encountered between the coast and Mansilla, a young man who was walking the Vad in the opposite direction. Good meal and great hospitality in the albergue there.
A couple of updates from Riano. We didn't find the Hotel Riano (later were told it's mostly closed), but we had a friendly reception, great meal, and very nice room at Hostal Sainz (on the upper road in town). A correction for Rebekah's guidebook: the road walk between Horcadas and the Remolina tunnel is way more than 1 km, probably more like 2 or 3. Even though we'd read great reports on the hostal in Ventasierra, we stopped in Cremenes to make the days more even. Great meal and room, and very friendly and accommodating people, at the Huelde (right over the bridge). Recommended.
We didn't have any trouble finding our way past the "spooky" old coal plant. Just followed the main-ish road and eventually it dumped us out at the hydroelectric plant right before Cistierna. Thanks, Laurie, for recommending the excellent Restaurante Moderne there. The albergue has a great library, but had no hot water the day we stayed there (the hospitalero warned us of this when we checked in).
Smooth sailing on to Gradefes, where the albergue is great. Ask in the bars in the centro for the key. Bring groceries: no bars are open for breakfast and it's a very long detour if you want to go to the restaurant across the river.
Mostly easy walking from Gradefes to Mansilla de las Mulas. We stopped at San Miguel de Escalada but could only walk around the outside; it's a shame it's only open two days a week. We did get a little messed up after Villacontilde. We tried to follow the instructions through the farm fields, and with the aid of detailed topo maps I'd downloaded to my smartphone things went ok all the way to the river. But then we ended up walking along a very busy highway for about 2 km into Mansilla de las Mulas. It wasn't dangerous (there's a wide shoulder), but it wasn't pleasant when the large trucks blew by. Maybe we were supposed to stay alongside the irrigation canal?
We caught a bus from Mansilla to Leon and had a rest day there. Next up is the Camino Invierno.