Itinerary: C1, C2
San Gavino is a simple transport interchange. The ARST bus arriving from Flumminimaggiore (C1, C2) will probably make its first stop in town in the small piazza right out the front of the FS train station from where trains depart for Oristano, as well as other places to the North, and Cagliari to the South. The train from Oristano (C1) and Macomer (C2) arrives at the FS station the exit of which leads straight onto the small piazza from where busses depart for the surrounding towns including that for Sanluri (C1, C2) which departs from just to the left of the station exit. Tickets for the ARST bus to Sanluri (the bus may indicate Cagliari as a final destination, check with the driver) can be bought from the small petrol station in the Piazza (to the left as you exit the FS station) but it may be closed when you arrive. There is a small bar in the piazza, and a bar in the FS station itself.
If you are following itinerary ideas C1 or C2 then it is best to pre-purchase a train ticket for San Gavino to Cagliari from the ticket office in the FS station before you exit the station to board the bus for Sanluri. Keep this ticket with you as you will need to use it later in the day to board the train at Sanluri Stato for the final journey to Cagliari.