Oyster card or national rail card?

The seven-day Travelcard will be cheaper than the maximum Oyster fare per day if you are staying for five days or more.

One other thing you need to decide is how many zones to put on your seven-day Travelcard. Most sites are in Zone 1-2, but Hampton Court is in Zone 6. If you are travelling from Heathrow Airport by Underground, that is also in Zone 6.

Rather than getting a 6 zone 7-day Travelcard, it will be better value to either buy separate tickets for those trips, or add some pay-as-you-go money to the Oyster cards on top of your Travelcard to pay for them.

The prices for all the options are at http://www.tfl.gov.uk/fares-and-payments/

If it were me, I'd go for the simplest. 1-2 weekly paper National Rail Travelcard (need photos) and Oysters with enough Pay As You Go cash loaded to get you in and out of London for the longer journeys. You can claim back the deposits on the Oysters, and any left over credit, when you come home or leave it for another trip. If you get the paper national rail travelcards you can travel any time and you benefit for the 2-4-1 if you want it at no extra cost....

Thank you both!

Since we'll have to pay the fare from Heathrow to Victoria Station anyway, I think we'll get the zones 1-2 7 day travel card on oyster. The fare from Heathrow would probably cancel out any savings we would get from the 2 for 1 offers. We'll be staying in zones 1 and 2 except for traveling to Hampton Court Palace, Windsor and Watford Junction. I'll ask when I buy the Oyster cards how much pay as you go money we should put on them.

"The fare from Heathrow would probably cancel out any savings we would get from the 2 for 1 offers."

I don't understand this bit, as the fare from Heathrow to Victoria would be broadly the same whether or not you bought 7 day Zone 1-2 cards on paper or Oyster, as it isn't fully covered in either case. Yes you would only need a Zone 6-Zone 2 PAYG fare as opposed to a Zone 6-Zone 1 fare on the journey to London before you have the travelcard, but that wouldn't save a tremendous amount.

However, the Tower of London is not offering 2-1 admission between 15 July - 3 September, which might be of more importance.

I see what you're saying Marco and you're right. Thanks! I had planned on going to the Tower of London on July 14 so I may still get the national rail 7 day. I was just trying to save time and do it all at once since we'd only be saving two child admissions.