Bus from Mansilla de las Mulas to Hospital del Orbígo

You will probably have to take a bus from Mansilla to Leon and then to Hospital de Orbigo from there.

Check the ALSA.es website.

Are you skipping Leon entirely? If you can, you should take the time to see the Cathedral as well as San Isidro in Leon, which are walking distance from the train/bus stations in Leon.

Buen Camino!

Kelly

Hei!
There are buses frequently from Mansilla to Leon from the bus station at the entrance to town. You can take a bus to Leon when you arrive in the afternoon, book a cheap hotel and get some time in the afternoon to see the cathedral. Or you can stay in Mansilla and take a bus at 8 in the morning. The bus cost very little, less than 5 euros I guess.
I do not know about buses to Hospital, but you can ask at the bus station when you arrive with the bus from Mansilla. Another option is to use some hours in Leon and take the train to Astorga at ca. 14 in the afternoon. The train station is on the same side of the river as the bus station. The ticket does not cost much either. You can check af http://www.renfe.es to find the time for the train.
You will then miss the bridge in Hospital.
Buen camino.
Ranthr