book from Dublin to San Francisco to London for around £330 return. Travel out until June 2013 ticket allows a stopover in Montreal Canada or New York on outward journey if required. YOU WILL NEED TO SELECT multiple destinations.
You can get the train/ ferry across to Dublin for around £35 single from anywhere in UK, which can be bought on the day at station. http://www.arrivatrainswales.co.uk/SailRail/