Hi, Margo.
Yo are sleeping first night in Santiago.
First bus to Astorga takes from 08:00 to 13:20.
Sometimes I've begin walked at 12:00 (when the bus from Madrid arrives) but you can begin walking at 13:30. I would walk to Rabanal would may be you prefer to stay first night in El Ganso. Less than 5 hours to Rabanal.
Second day, (from El Ganso or Rabanal) to Ponferrada.
Third day, Villafranca del Bierzo
Fourth, Cebreiro
Fifth, Triacastela
Sixth, Sarria
Seventh, Portomarin
Eighth, Palas de Rei
Nineth, Arzúa.
Tenth, Santiago.
These are the "marked" daily walks, but there's a lot of albergues, towns and options.
For example, From Cebreiro I use to continue to Calvor (5 km. before Sarria) because when I arrive in Triacastela use to be between 11:00 and 12:00 and it's to early to stop, I prefer to continue. So, next day you continue to Portomarin. As an experienced walker, when you arrive to any albergue and you know there's another albergue in 5-7 km, many times you will prefer continue, because, small albergues has something "special" and different than the ones in big towns.
In October there's no problems to sleep in any albergue.
Buen Camino,
Javier Martin
Madrid, Spain