I will be arriving in Heathrow at 6:25 AM; then I need to go to Elephant & Castle.
I believe that I will need to take the tube to St. Pancras; and then is it best to take a bus or train to Elephant & Castle??
If I should take the train, which one?? Northern Line or the Thames Link??
If I need to take the bus, which one??
What is the difference in cost? I will be in London for 6 days; should I buy the Oyster card??
THANKS!!