Train is not an option! The last train to Lisbon leaves Faro at 17:00.
The last Renex Bus to Lisbon leaves Faro Bus Station at 20:00. He will need at least one hour to clear immigration, collect bags and get a taxi into Faro Bus/Train Station.
However, there is an overnight Rede Expressos Bus service leaving Faro Bus at 01:30 arriving Lisbon at 07:00 and connecting with a bus arriving in Caldas at 08:10.
For details goto to my blog:
http://barlaventostravelblog.blogspot.com/
Scroll down on the right till you see a panel entitled
»»Algarve & Portugal - Travel Transport Links
In there you will find links to the relevant timetables including one entitled
"Rede-Expressos - National Bus Timetable - Updated"
This will take you to the Rede Expressos website. (Only in Portuguese)
I would not recommend driving as if you come by the A2 motorway you will also have to pay tolls both ways and at that time of year the weather can be the pits. If you take the old IC1 road, you will be restricted to 90kph. It will take as long as the bus.
