Walked to the Argeles Sur Mer train station from Villa Failte and took the train to Perpignan (about 15 mins / 36 Euros for 4 of us). When we got there weren't sure what way we should go (typical tourists !) but on leaving the old station we were pleasantly surprised by the clear directions and the wide tree lined street that leads to the city centre (12 minutes walk away).
On arriving at the centre there are loads of cafes and restaurants as well as a well signposted tourist information office. If you look down the beautiful canal you will see a bridge at the end ... this is where the tourist train/bus starts / finishes. It is a 45 minute journey through the streets of central Perpignan and is a great way to start your visit. Note the journey is not "hop on / hop off". Cost was 7 Euros per head and we though was well worth it.
We followed that up with a nice al fresco lunch at one of the cafes overlooking the canal and then a spot of shopping ... there are two or three excellent streets for shopping just beside the train/bus stop.
Ashamed to say that we never visited any of the fantastic historical sights in Perpignan ... next time !! Most definitely recommend going there and spending some time. The train is a great way to get there and back too.