I have been told that it is possible to get from Barcelona to Cerbere FR without changing trains but I cannot find that service on the Renfe site. I have traveled as far as Portbou in the past but now need to cross the border into France. Anyone done this? Travel will be Monday, May 12th, 2014. I will be disembarking a ship around 8AM
I strongly doubt you will have a direct journey.
Neither are you likely to find train schedules for journeys that far in advance.
Suggest you use www.bahn.de and an imminent date to find what will be very likely.
You need to change trains AFAIK. Fastest way is to take a TGV to Perpignan and then a regional train back to Cerbère