It's a matter of gradings. The black-cab drivers go through an extensive and gruelling process of learning both the approved routes and the shortcuts, as well as safety and security tests. And their regulated fares can work out quite high. Minicab drivers don't have to jump through the same hoops, but can get a basic security and safety certification from TfL; they can only take pre-bookings and can set their own rates, so if you know of a reliable local firm for straightforward journeys, then, yes, it pays you to stick with them. Under I don't know so much about, but I assume they're using minicab rules and status.

"The world is your Oyster." I think that's where the saying comes from.

I sometimes use buses and have never had a problem hailing a black cab in London. I find that black cabs are cheaper than Uber.

We were in London twice in the past 13 or 14 months, and I am somewhat limited in stair climbing and walking.

We found that using citymapper.com gave us the largest number of options for public transport, with times included. We also were using the TFL tools, but fairly often, citymapper.com gave more choices. Cutting down on walking distances, we were sometimes able to hop a bus before or after a tube, or for just a few blocks.

I may be wrong, and since this is Fodors, someone will surely tell me if I am, but somehow, the citymapper.com app seemed more intuitive in searching for the least amount of walking.

Uber drivers get a terrible reputation for unsafe driving and finding circuitous routes in London among my friends and their co-workers who live in London. This is purely hearsay, so take it for what it's worth. I did see an Uber driver drive in an opposite direction on a one-way lane in a Heathrow garage, but who among us hasn't, right?

AFAIK uber doesn't require any expertise or knowledge of anything . . .

My niece who lives in London also rcommends citymapper, although I have found the maps app on my Android phone does fine.

I share janisj's aversion to Uber/Lyft in London. And I have an aversion to Uber anywhere, although I did recently use Lyft in DC.

While the tube is usually faster, the buses are more scenic. I love sitting up top, ideally in front, so I can admire the upper parts of the buildings which have generally not been modernized.

It doesn't appear that Lyft is in London. From their website, it looks like they are primarily in the US.

Reporting back now that I'm home. Thanks again for all the advice.

I relied a great deal on three apps: citymapper, a tube app and a bus app. There were not many steps at St. James Tube Station and my friend was more able than I anticipated. We used the tube a lot using a lift when available, some buses and a black cab once. We both agreed that taking the tube was great fun. Never had to wait more than a few minutes for a train. As my friend is a Brit we relied also on her phone's GPS for walking directions -- no internet roaming charges. So nice not to open paper maps while out and about.

At the last minute I booked JustAirports for my ride from Heathrow to my hotel at a flat rate of 32 GBP, plus 4 GBP for airport parking, plus a small tip.

We had nice weather in London. Tossed out plans to visit museums and spent our time outdoors as much as possible: St. James Park, Covent Gardens, Portobello Road, Brixton Village, and sometimes just enjoyed being in the city.

St. Ermins Hotel was nice and well located.

Thanks for reporting back! Glad you had a good trip and lucked out with the weather.

Sounds wonderful! Thanks for the update.

What bus app did you use?