I'll be the dissenting voice here. I had absolutely no problem with the train to Southampton, even with luggage (solo traveler). Trains were (in 2002 ... probably no different now) every 15 minutes, and the travel time from 1 hour 15-to-40 minutes, depending on local/express (trains on the hour and half hour the fastest). You still need to take a taxi from the station to the ship, which is about 5 to 10 minutes away. And, the fare was quite reasonable, about 21 pounds at that time, if I recall correctly.