Hello,
You can easily use Streetview in Google under Maps to explore the path.
Between Castrillo De Polvazares and Santa Colomba is the LE-142
The camino crosses this road. Easy to find because at this cross, there is a blue line heading to Santa Catalina/El Ganso
At this cross, there are the following signs, a little bit blurred by Google
< 6 ASTORGA
SANTA COLOMBA DE SOMOZA 10 >
In fact, at the right side of the LE-142 is a separate trail you can use for a while.
It is best to follow the LE-142 when this trail is heading to the right.
In SANTA COLOMBA DE SOMOZA is a road to going to the North to EL GANSO.
This one is not StreetViewed. But you can see it in Maps.
Maybe it's better to continue following the LE-142 to
< 6 RABANAL DEL CAMINO
Just before the centre of RABANAL DEL CAMINO where you see the sign
<22 ASTORGA
FONCEBADON 6>
the camino touches at the right side, also visible in StreetView.
I walked two years ago on the LE-142 from Astorga to Castrillo de Polvazares. There is some traffic but not so much.
You will not get lost.