It’s really pretty amazing how many nice little cities/big towns there are along the Francés. I think you’ve got so many choices that you can be pretty certain that if you feel like a day off, you won’t be far from a good option.
If the weather is nice and you fancy sitting in a café by the river and watching the world go by, I think Molinaseca (as
@Anamiri suggested) is a good choice. A little bigger, i think, would be Villafranca, which has some nice churches, nice gardens, etc.
For totally just chilling out in a rural spot, Morgade would be my choice. Absolutely wonderful people, comfortable place, lots of little walk to take, but it’s all rural countryside.
My pal (and forum member) @Juanma’s
albergue Maralotx is a great spot, in the small town of Cirauqui, just 7 km beyond Puente La Reina. I think the suggestion to take short days into some of these places is a good suggestion, because in some of them you will not likely find a way to spend a full day plus the afternoon of the day you arrive, unless you are just in total chillout mode. (Same for Morgade, 12 km beyond Sarria).
Threads like this make me think that maybe it’s time to go back to the Camino Francés!