Much thanks for all the help. Of course you're right about Mansion
House or Cannon St being better choices. I was fixated on the
Central Line because I used to live near it. I'll give my friend your
information (the cab fare costs were especially helpful) and let her
choose.

Just after I posted my earlier message, I checked the London
Underground website. It recommends your route: Heathrow to Mansion
House, changing tubes at South Kensington.

Thanks again
Alan

Does anyone know the approximate cost and length of time for a cab
from Heathrow to the Globe?

Fifty quid as a minimum if she's getting a black cab.

What about cost and time for a cab from Paddington to the Globe?

Twelve-fifteen quid

Any thoughts about just taking the tube? -- Piccadilly line to
Holborn, Central line to St Paul's, and then walk?

Over a mile from St Paul's. Not what you want after any kind
of journey with a carryon.

Piccadilly to South Ken and then District to Mansion House
or Cannon St would be my choice.

Angela