Island2Dweller

You can do it by train. A "walk up" flexible "off peak single" ticket (valid after morning rush hour is over) costs only £27. The downside is that it takes two and a half hours and requires two changes. Train to Redhill - change - train to Tonbridge - change - train to Dover. I'd be quite happy with that journey, but I routinely use public transport just about anywhere in the world. You'll have no problem getting a seat. There is also a train route with only one change (at London St Pancras) but it costs about twice as much and isn't faster. Using National Express coach for this journey isn't feasible. Private Hire pre-booked car service will be quicker but cost a lot more. A taxi off the rank at Gatwick is also possible, but will cost more again.

National Express coach goes to Victoria coach station. A couple of miles from Charing Cross, so not particularly handy fo your hotel. Cheapest (and often fastest) is by underground (tube). Will take under and hour and cost less than £6 per head (so long as you use a contactless bank card / smartphone / smartwatch). Piccadilly line from Heathrow (the trains start at the airport so you will always get a seat). Change at Hammersmith (cross platform, about 2 yards walk) to District line to Embankment. Five minute walk to hotel. Perfectly safe, at your time of day it won't be too busy. Not recomended on a very hot day as not air con. Convenient option is a pre-booked private hire car. Many options such as Blackberry and Simply Airports. The driver will meet you at the arrivals door. Price is agreed and fixed in advance. Comfortable but costs much more than the tube.

Safest? London is (by international standards) an incredibly safe city. Just use usual "big city street smarts" and you will be fine. The train/DLR combination is perfectly safe if you prefer speed and value. A pre-booked private hire car is definitely simple, but won't be quicker and will cost a lot more than public transport.

I don't think Heathrow is any less busy on a Sunday. If everything works like clockwork, you should make it, but you have zero contingency for any hiccups. I would want to have a pre booked private hire car waiting. As mentioned above, there is no guarantee that any Uber driver would want to accept this trip. Furthermore, if you use Uber, you have to make your own way to the designated car park (where Uber drivers have to wait), whereas a Private Hire driver will meet you at the arrivals door.

The Eastern flight can be bought as a through Air France itinerary, they do interline

If you want to fly into Southampton from the US you don't have many options. You need to look at KLM (changing in Amsterdam) or Air France (changing in Paris). You need to weigh up the ease of using Southampton with the extra hassle of a transfer at either AMS or CDG.

I understand the sentiment. But just to alert you to how life in London has changed. Plenty of places in central London (bars/cafes/restaurants) are now card only. Bring cash and you will be politely turned away.

I'm slightly puzzled by the number of posters on this forum who seem convinced that taking their credit card out of their wallet will cause them to lose it. Use of cards (or smartphone or smartwatch) is now the dominant payment method for travel in London and it works just fine for millions of folk here. You can still buy an oyster card if you wish, but that has a £7 (non refundable) upfront fee and is valid to fewer destinations than bank card.

The Novotel is literally at the door of Greenwich railway station. It's also only a five to ten minute walk to the historic core with the naval college etc. It's also connected to the DLR network. Using that you can make one change (at West India Quay) to then get the Elizabeth line to Heathrow. If you book an "advance" rail ticket, (it's a particular ticket type, it is valid on the booked train only) you can get four people from Southampton to Greenwich for about £75. You can buy "walk up" tickets on the day, but that will cost about £130 for four. You would change at Waterloo and London Bridge, which sounds daunting but is not as hard as it sounds. Escalators and lifts available, so you don't need to haul bags up stairs. A car service is obviously door to door convenient but will cost much more. Traffic is unpredictable. About once per month (very rough average) a problem with the Blackwall tunnel will cause Greenwich to go into gridlock. Never any way to predict.

The area is not as busy as the West End, but it's no longer the case that the City is deserted in the evening or weekends. The Bank/Tower location is ridiculously well connected for tubes and buses. As mentioned above, rooms in Hub locations are very small, and if you have large luggage that can be an issue.

Indeed, you're correct. They've changed the rules again. It used to be that the purchase charge became credit after a year. But now the £7 for a new card is now is never refundable. All the more reason to do as most folk in London do and use a bank card / phone or watch instead, rather than buy an oyster. Additionally, oyster is valid to fewer destinations than card/watch/phone.

If you decide to use the train, but don't fancy walking back from the station to your ship, get off at Grays. That's the stop before Tilbury. There will be taxis waiting there, whereas you won't get one at Tilbury. There are also more trains from London to Grays than to Tilbury.

Yes, you can get a refund on the cash balance, but you don't get the £7 that it costs to purchase the card back. (After 12 months, that £7 becomes available as travel credit, but not before).

Oyster was innovative when it was introduced two decades ago, but it is now "old tech". It still works, but it is no longer the most used payment method in London. A contactless (wave pay) bank card or smartwatch / smartphone is all you need, and cheaper because it avoids the non-refundable £7 that oyster costs. You mentioned "find tube" but depending on the precise location of your hotel, the new Elizabeth line may be better. Slightly more expensive but much quicker, much bigger and more comfortable carriages. And air conditioned.

Most hotels in London can provide breakfast but the majority will charge for it. You need to check the details when booking.

If you are going direct from Heathrow to Grays/Tilbury on a Saturday*, you wouldn't use the tube. Take the Elizabeth line to Stratford and change there (same platform) for the c2c train to Grays. These are "full size", air conditioned, trains. They're nothing like the cramped conditions of the Piccadilly line. * The day of the week is important. The option for the same platform change at Stratford is only possible at the weekend. Weekday c2c trains don't stop at Stratford.

Are you trying to get to London from Rotterdam? Simplest is the British Airways flights to London City (LCY). That's London's best airport, small and very quick to get through.

And if you are happy to carry your bags a few yards, the Cutty Sark stop on the DLR is barely two minutes walk away. It has a lift to the platform, no worry about steps

Even in the early hours of the morning, the road journey to Gatwick is purgatory. An hour might be possible, but I would not bet on it. I would rather stick needles in my eyes than do that journey by road. On top of which, Gatwick has a large 'first wave' of flights so it can be very busy at 5am. If you want to keep that flight, I would book a hotel right at the terminal in Gatwick such as the Premier Inn by N terminal.

Using both boarding passes for only one person is likely to delay the plane as the headcount won't reconcile to the manifest.

If you do book the extra seat, remember to do on-line check in for that mythical person so that it appears as if the seat will be occupied. Even then, if the flight is oversold, BA may still put someone in it as the flight boards. Their system will tally who has boarded (at the gate) and if it shows your extra seat isn't occupied, they may move someone into it. Again, only if they are oversold and have standby passengers waiting at the gate. Not exactly likely but can happen.

If interested in maritime history then a visit to Portsmouth is certainly worth it. But it is barely 20 miles between Portsmouth and Southampton, whereas it is 75 from London to Portsmouth. Unless you have other plans for London, you're spending a lot of time on travel that you don't need to. Go direct from Heathrow to Portsmouth. Have plenty of time there. Stay overnight then the short hop to Southampton the next day.

That's Uber marketing. They are not connecting to any drivers when they give you that estimate. As stated above, I would not assume that any drivers local to Heathrow want a multi hour trip down to Southampton

e-sim..... If your phone is fairly new, it'll probably support adding an e-sim as well as your regular sim. This allows you to keep your normal number (so if anyone from home needs to get you in an emergency, they will get through) but use the "local" e-sim for local calls and data. There are lots of operators offering these for about £10 or $10 a month - much cheaper than the $10 a day your operator wants you to pay. You do need to be reasonably tech savvy for the first set up of an e-sim.

See my comment above about the possibility of dreadful queues at the tunnels.