Half a day in London

[peri]

If Hull Trains behave I will be in London 2nd May from 11:00 to 20:30. It is a long time since I last visited and at present I cannot walk very far.
I am thinking of tube to Wimbledon to play on the trams and then ending up roaming on the DLR, possibly by bus to Woolwich Arsenal from Elmers End. Then find somewhere to eat during rush hour and slowly back to King's Cross.
I am mainly wondering just how much I should put on my Oyster card, considering it could be a while until I next visit.

 

[Fawkes Cat]

I think there are two answers, but someone who knows properly should be along soon:

1) £9.80: I don't think that the trams or DLR go further out than zone 4, so per http://content.tfl.gov.uk/adult-fares-2018.pdf, a £9.80 daily cap will apply
2) Nothing. Don't use your Oyster, but just use a contactless credit or debit card instead, tapping in and out just as you would with an Oyster. The appropriate cap will apply (assuming that you use the same card all day) and you don't have to worry about topping anything up.