This is a very long trip and not an easy one.
Apart from driving directly by car via Madrid, which will take in the order of 9 hours driving according to Google Maps, the other options would be:
1) Long distance Bus
- Valencia to Madrid
- Madrid to Lisbon or Guarda
- Lisbon or Guarda to Covilha
2) Train
- Valencia to Madrid
- Madrid to Lisbon
- Lisbon to Covilha
3) Plane
- Valencia to Lisbon/Porto
- Train/Bus from Lisbon/Porto to Covilha
If you could indicate which of the options above interests you, I would be pleased to try provide more information.
