I went a couple of years ago when London were there but it was part of a holiday via Barcelona. I got a bus from Barca to Girona and then the Frogbus to Perpignan before flying out of Perpignan. If you can you'll be better flying direct.
In fact we bumped into Frank (who went to Toulouse) but he's booked to fly back on Sunday and Sky switched the game.
I stayed in the IBIS which is cheap enough but to be honest Martin it's a bit far for you to walk into the centre. Best best is the Mercure or the Kyriad where the teams and Sky pundits normally stay.
There is a service bus that stops by a small tower in the centre that takes you too and from the ground and I think it was about 20 mins.
It's too short notice for me to get time off work but I'd love to go.