I have not yet done it but it is on my plan when I hit
camino frances next time. this is the description I made based on google maps:
From albergue in
MANSILLA continue along Calle Puente, veer L across Plaza s Nicolás, pass the fine remains of the murallas, cross the 8-arch puente over río Esla, and follow senda parallel to the road. Pass one dirt road branching L and reach the
1.1km second just as N601 joins from the R.
To/via Villaverde de Sandoval: Turn L to this second straight dirt road, cross a dirt road, turn R in a T intersection then 20m later turn L to another dirt road. Turn L in a T intersection then 20m later turn R and this dirt road soon joins a tarmac road that in about 1.5km reaches the impressive ruins of
3.3km 12C
monasterio de s María de Sandoval. The road continues to
+0.6km VILLAVERDE DE SANDOVAL (F), but you can turn R off it immediately after the monastery, to a dirt road that in 500m reaches CV162-29. Turn R and follow it to the second intersection. Turn L here, to another dirt road, and follow it straight, passing
+0.4km MANSILLA MAYOR (F; late-gothic s Miguel (magnificent mudejár ceiling)) to the R, straight in all intersection (it meanders a little), past
+0.3km VILLAMOROS DE MANSILLA, to the end when it bends R to reach
5.5km N601 and the main route where it becomes senda again.
it can be a bit confusing with all the straight dirt roads/tracks but hopefully it's detailed enough so that you can't get lost.