Need a little clarity on tube and rail costs

Tap and go will automatically work out the cheapest method. In your example, one day travel from Heathrow and 6 days regular travel in zone 1-2, then that is £16.30 + (6 * £8.90) = £69.70

This is cheaper than a weekly z1-6 but more expensive than a weekly z1-2, which makes sense (to me at least)

The differences are quite subtle-
1 If you are travelling elsewhere in the UK by train and qualify for a railcard (Two Together/Senior etc) then you get a 1/3rd reduction off the price of a travelcard. If it is a senior or disabled railcard you get 1/3 off all non peak tube fares, including the daily/weekly cap, using Oyster (but not contactless).
That may be the case if you go to Bletchley, Windsor or Hampton Court for instance (especially if you intend to use the Two for One Offer at Bletchley Park).
2 There are minor differences in favour of the travelcard regarding afternoon peak fares
3 If you intend to use the Thames Clipper/Uber boats a few times, fares are cheapest using a travelcard, as opposed to contactless, sufficiently so to swing the pendulum towards the travelcard.

So it depends on your overall plans.

The Elizabeth Line has a 7 GBP surcharge over the cost of taking the Piccadilly Line from Heathrow.

TFL has a website devoted to fare capping. It should answer all of your questions.

From Sunday 1 March the Elizabeth Line surcharge will be £9.60, which will leave you just 80p short of the daily Zone 1 to 6 cap. So one more journey (tube or bus) and you have reached the day's cap, after which all journeys are free.

Whereas the cost of paper Elizabeth Line tickets is unchanged, due to the national fare freeze on rail fares.

The Elizabeth Line will be, the tube will be £5.90.

Thanks for the responses. I just discovered that the Heathrow Express train is only £10 if you book far enough in advance, so I think we will go that way, since it will be cheaper than the Elizabeth line and is even faster, and Padding is our destination as well.

Thanks for the info about the Clipper for the Travel Card. But it looks like the difference in cost is not enough to overcome the cost of purchasing the Oyster card, unless you took a whole bunch of boats.

Also, to be clear, the cap on bus rides is separate from the cap on train travel? So getting on a bus when you are close to the cap on the tube will not push you to the tube cap - correct?

Regarding train travel, we are indeed planning on going to Hampton Court, and also possibly to the Red House in Bexleyheath. My wife and I are both seniors. So would it be cheaper to purchase train tickets instead of using the Pay as you go system, especially if we travel off peak?

I went back and looked at isn31c's reply and realize now that the reference to the national rail card is for traveling outside of the London area. I also looked at the TFL web site and don't see any discounts for seniors in the fare list, so I assume that is not an option.

Also, to be clear, the cap on bus rides is separate from the cap on train travel? So getting on a bus when you are close to the cap on the tube will not push you to the tube cap - correct?

No. You won’t pay more than the tube cap. If you take a combo of bus and tube rides, fare is capped at the tube cap. If you only take buses, then the fare is capped at the lower bus cap.

No, the National rail card is for all National Rail services, so includes all London Overground trains (like the slow trains to Watford Junction for Harry Potter), the Elizabeth Line, and the Heathrow Express, and all suburban main line trains. So the £10 Early Bird fare becomes £6.65 on the Heathrow Express.
A paper ticket on the Elizabeth Line with a railcard from Sunday is £10.50 (full paper ticket fare is £15.80, just 30p more than the contactless/Oyster fare)..

Regarding train travel, we are indeed planning on going to Hampton Court, and also possibly to the Red House in Bexleyheath. My wife and I are both seniors. So would it be cheaper to purchase train tickets instead of using the Pay as you go system, especially if we travel off peak?

Yes, but don't buy 2 x senior railcards, buy 1 x Two Together Railcard, for the same price of £35. Both Hampton Court and Bexleyheath are within the London Zonal System- Bexleyheath in Zone 5, and Hampton Court Zone 6.

So, just looked up the railcard info. It does seem like an awesome deal if you are visiting a for a long time. But with a 10 day visit and maximum of 2 or three train journeys, not sure if it would be worth the £35 cost. I'll have to do the math.

I'm confused. I thought loading a Senior Rail Card on my Oyster Card (which a TfL employee did for me last year) meant I would receive a discount on all off-peak Underground trips. Am I misinterpreting this webpage or overlooking a key caveat?

https://tfl.gov.uk/fares/free-and-discounted-travel/national-railcard-discount?intcmp=54723

acraven - you’re right that loading your Senior railcard on to an Oyster does give you a discount. That’s why I have an Oyster rather than just using a contactless card.

But it won’t be worth it for many visitors. The OP appears to be doing only 2 or 3 short rail journeys and it’s certainly not worth buying a railcard at £35 and an Oyster at £10 just to get the discounts on TFL services for a short visit. But for others like you, with different plans, it may be worth the effort. Especially if you are likely to come back and use the Oyster and particularly if you still have a valid Senior Railcard.