Help plan my Tower of London day

Option 1 with a twist.

Tower of London first thing. Second, Leadenhall Market for lunch OR pub lunch at the venerable The Ship pub. Next off to the Sky Garden and then stroll to the lovely St Dunstans in the East.

Grand mix of old and new architecture and what makes London, London.

Claudia, thanks for your reply! I think The Ship pub looks great! Also, I had St dunstan on my maybe list, so I’ll be sure to stop by. I’m curious, do you think combining St. Paul’s cathedral is too much for one day? Too far to walk from the tower? Maybe I should only plan on the Tower of London for that day and combine the other things on a different day.

Whatever else you do that day, do Tower of London as soon as they open in the morning. As the day goes on, the Tower gets more and more crowded. Huge crowds build up. People are supposed to have timed tickets and leave when they're finished touring around, but many don't. Many stay for the rest of the afternoon, strolling around the grounds, going back up on the walls for a second look around.

You can get lunch within the Tower of London if you want. The Armories Cafe has great sandwiches, salads, chilli, soups, plate lunches, drinks, coffee, tea, desserts.
There's no need to rush through the Tower. If you want to have lunch there, and then see more of the Tower, do it. You've already paid to get in, obviously, and probably will never be back.

Another option is to walk to the river pier right beside the Tower of London and take the river boat to Greenwich to see the Observatory and the Maritime Museum. That would take the rest of the day and then you could take the Thames Clipper boat back to the Westminster pier from Greenwich.

Regarding your option 3: Going from Tower of London to St Paul's would be a good plan. The Number 15 bus runs from the Tower of London to St Paul's. After your visit to St Paul's.......
The Number 15 then goes on to Trafalgar Square, where you could get off and walk to Westminster which is mere blocks away.
If you still have time to kill when you get out of St. Paul's you could pop into one of the museums on Trafalgar Square.
Or walk straight across the bridge from St Paul's to the Tate Modern.

Your "Tower of London > walk across Tower Bridge to Borough Market for lunch > then to Tate Modern" plan also works well. There are not many places to sit down after getting your food at Borough Market--three or four picnic tables which get occupied very quickly. Many people just walk around, eating their sandwiches, but if this is not your idea of an enjoyable dining experience, just be warned and maybe eat elsewhere.

I like Claudia's suggestions, too.

OP adding St Paul’s on your Tower day would be dependent on your stamina. 20 minute stroll from St Dunstans.

Might look on line to see if evensong at St Paul’s was occurring. An enjoyable way to experience a church service. Uncertain if its free these days so research.

Do the tower first thing in the morning. Once you get inside, go see the Crown Jewels FIRST. You will be glad you did! We did this (in 2019) based on Rick’s advice. We waited in a short line for maybe 8 minutes. After we were finished and got back outside, the line for the jewels was about 50x as long. It was crazy!!! Everything else within the tower was easy to get into. We then did the walk across Tower Bridge to Borough Market. Then afternoon tea at Fortnum and Mason. Was one of my favorite days ever.

I agree that first thing in the morning is best and head for the jewels. Also, there is a guard standing nearby in full red outfit and bearskin hat, and close enough for photos first thing in the morning. By 10:00 we wouldn't have been able to get near him to get a decent photo.

As far as doing multiple sites on your Tower day, consider how long you like to linger at historic places. We spent 6 hours at the Tower and didn't have time for other sites that day. Having said that, Leadenhall Market is a great place to stop to eat, you may end up spending an extra hour there as well just wandering the shops.

If you really want to get the most of your Tower of London experience, watch the 8 episodes of “Inside The Tower of London.” You can buy the episodes on iTunes. I learned more from watching the episodes than I did on my three visits there.

There are more than 8 episodes of that TV series, or are in the UK. It's been through several series now. Maybe it's accessible through On Demand viewing.