Elevator/escalator access @ Heathrow & Gatwick

Both the easiest and cheapest way to get from Heathrow to Piccadilly Circus is to take the Tube. It's a direct shot on the Piccadilly Line and the cash fare for a single ticket is 4.50 GBP. At Heathrow the trains run above ground. The Piccadilly Circus station has escalators. However, the Transport for London site says that "escalator service at Piccadilly Circus is reduced until further notice." Ask for an update at a Heathrow Underground station. If necessary, you could take the Piccadilly Line to Green Park (one stop from Piccadilly Circus) and one of several bus lines from there to Piccadilly Circus. Green Park has escalators.

Bus #38 runs directly from Piccadilly Circus to Victoria. Buses run every 3-4 minutes and the ride takes less than 15 minutes.

Take a Southern train from Victoria to Gatwick. It's only a little slower than the Gatwick Express and is much cheaper. Trains run about every 15 minutes.

Edna - Here is a link to Transport for London . This should help you plan your route.

Even through Piccadilly circus has an escalator, there are steps out to the street level. Very few of the London tube stations are step-free. If you cannot manage any steps, then you may want to consider taking the Heathrow Express or Heathrow Connect to Paddington and then switching to a taxi.

To Gatwick, I would also suggest a taxi to Victoria Station and then the Southern train to Gatwick.