July 10th Heathrow --> Tain to Trafalgar square area + 2for1 National Rail in London

Which hotel near Trafalgar Sq will you be staying at? This is a big area so knowing exactly where your hotel is may make a difference.
Also, I don’t understand your last sentence…

Hi Amanda,

I’ll be staying at Grand Hotel Trafalgar Square.

So what I’ve been reading about the 2for1 is that you need an active national rail ticket for the closest station to the attraction.

Since I’ve never been to London, I have no idea which that would be. However, I went to the national rail website and used the tool to plan my journey.

I selected July 10 from London Charing Cross to London Waterloo one way for 4 people. Then selected the reserve on the 12th. This way, I would have round trip tickets valid from 10-12.

I am not sure if that’s how it works or if that would even qualify me.

Don't forget this term:

All tickets should show that you have travelled to the attraction by train, whether that be ‘London Terminals’ for l 2FOR1 London or other offer attractions, or the train station nearest to the attraction itself. Tickets that have a destination too far from the attraction’s location may be denied by attraction staff

A ticket for a journey inside central London that would take a few minutes to walk, less than your journey from Waterloo to the attraction is unlikely to cut the mustard.

To buy a ticket from Charing Cross to Waterloo or Waterloo East would be unlikely to qualify you for the 2for1 offers, as anyone would see that as a ruse. It just isn't a journey anyone would sensibly take on a mainline train, when there is a cheaper tube alternative.
However if you travelled into London on the Elizabeth Line and purchased physical tickets (rather than using Oyster or contactless as most people do) that should qualify on the 10th as the Elizabeth line is a National Rail service, not a tube line.
Probably the most sensible (and undoubtedly qualifying way) is to buy the cheapest possible Oxford to London advance fares (out on the 10th, back on the 12th) which should be £5 each, each way- so only £1.30 more than Charing Cross to Waterloo East.
But how much that really saves you on buying family tickets at each attraction I don't know. For instance at Westminster Abbey one child gets in free with each adult anyway.

For the Grand Hotel, Trafalgar Square the most sensible station would be Embankment, on the District Line.
It doesn't really make sense to change there one stop to Charing Cross, as there is so little difference in walking time from either station.
So Piccadilly line to Hammersmith, change to District Line.
So unfortunately for you using the Elizabeth Line then changing off that, just to get 2For1 is not the most sensible option.

All good info, thank you all.

So what I'm planning is to get to the Hotel on the 10th, then go to the British Museum.
On the 11th - 12th is when I need to figure out the 2for1. The trip from Charing Cross to Waterloo was just something I threw out there, figured it wouldn't work.

isn31c, you're suggesting Oxford to London, do you have station ID's? Sorry I don't know specifically which ones they are. Also, where would I purchase the tickets?

We have a problem. Great Western have increased their advance fares from Oxford [OXF] to London Paddington [PAD] from £5 to £12.
Even with a groupsave ticket for the 4 of you that would be £36 for each day. Would you get enough savings?
So the cheapest way to do it is to buy a Groupsave off Peak Day Return for each day at £24 for the 4 of you from Tilbury Town to London Fenchurch Street. There is an operator only on line discount to reach this fare so it has to be booked through the C2C [the operator's] website- https://www.c2c-online.co.uk/
But can be collected from any National Rail Ticket Machine.
Tilbury Town is the first station where you are outside the Zone 9 TfL ticket boundary.
Really important note- the 1st arrival at Fenchurch Street on this ticket is at 1013, so you could not sensibly be going into the Tower of London before 1030, or anywhere in the Westminster area before 1045.

I thought it was recognised that a ticket from Queenstown Road to Vauxhall and return was recognised as meeting the rules for 2-4-1 tickets?

Tickets for London attractions now should be to London Terminals or somewhere actually close to the attraction as my quote from the terms indicates.

Recognised by whom?
This has been discussed ad nauseum before. and QR- Vauxhall is very questionable.
I quote for the second time on this thread-

All tickets should show that you have travelled to the attraction by train, whether that be ‘London Terminals’ for l 2FOR1 London or other offer attractions, or the train station nearest to the attraction itself. Tickets that have a destination too far from the attraction’s location may be denied by attraction staff.

Any attraction would be perfectly within it's rights to say that Vauxhall is not the closest terminal station (and Vauxhall is only technically a terminal station, nothing main line actually terminates there) or the closest station to the attraction. If asked did you walk from Vauxhall (if so why) or did you use the same Oyster Card /contactless as you could have used all the way from QR. Think very carefully before answering that and committing perjury.

At the end of the day you are trying to mis-use a system which is designed for day visitors from outside the boundaries of London to encourage off peak rail use. It is very interesting how heavily c2c rail promotes the scheme. Taking you from beyond Zone 9 was deliberate to remove the slightest element of doubt, while still actually being unlawful, as the rail ticket in question hasn't been used- a fact that could readily be ascertained.

Community Guideline 7 applies.

For your hotel I would Piccadilly to Baron's Court, then District line to Embankment.

jgdh,

Is that from Heathrow to get to the hotel?

Thanks