US cruisers embarking at Southampton should definitely plan to spend a day or two here before sailing. Reasons:
1. The usual "avoid the stress" rationale in case of any flight irregularities.
2. Get over the jet lag before the cruise.
3. You can really have a nice time "down South" in England.
1. National Express busses run regularly from both Heathrow and Gatwick to Southampton.
2. If you stay at the Ibis or Novotel you can literally walk to the hotel from the bus station or the train station.
3. The Ibis and the Novotel are co-owned by Accor and share a parking lot. The Ibis is about half the price of the Novotel, and is very nice. There is also a Europcar rental agency in the lobby, which is extremely convenient.
4. If driving on the left and driving a stick shift doesn't bother you, renting a car and driving around is a lot of fun. Worthwile destinations include Winchester and the New Forest, among many others. You can also catch ferries to the Isle of Wight.
5. Taxis to the pier from virtually any hotel in Southampton are roughly a 10 minute and 10 GBP proposition.
Heathrow and Gatwick are approx 80/90 Uk miles from Southampton and they are all linked by Motorway so you are probably looking at around 2 hrs depending on any stops. National Express is the coach service
As most flights from N America arrive early morning Uk time and most cruises depart in the evening you can easily do the transfer on the same day.
Southampton is a modern city but if you are looking for historic buildings forget it as the town was flattened by the German Airforce 1942.
I agree that for a value precruise hotel the Ibis and Novetel are ideal and you should be able to see your ship if your room overlooks the sea.
I you want to explore the area then travel west in to the New Forest where there are an abundance of historic villages and towns. If you hire a car (we do have automatics) go west and you will not have to travel on the motorway.
If you want to stop over in London precruise then trains leave from Waterloo station platforms 14 / 15 / 16 depends, every hour. Get the fast train and it will take just over an hour. The train station at Southampton is a short taxi ride from the dock.
Do remember that the Titanic made its final trip from Southampton so do count the life belts !!!!!!!