Lessons Learned

Happy to say that I didn't lose anything or get lost on my trip. Before I forget them, here are the lessons I learned:

1. I must stop looking for the steps-free access to the westbound District Line platform at Paddington. Yes, it is possible to take the lift up to the ticket concourse/street level from the eastbound platform, but steps-free access back down to the westbound platform does not exist. Advice to self: Deal with it, get a lighter suitcase, or use the Circle/H&C via Hammersmith to get to Heathrow. 
2. Aer Lingus from Hartford via Dublin is the way to go. Doing immigration at Dublin saves much time and hassle over the lines at Heathrow. It was so quick and easy on the way to the UK that I hardly realized (at 4 am) that I had done it, but I have the stamp in my passport as proof. Coming back was a bit more complex, with three different segments to the pre-clearance for US-bound passengers (re-screening of all carry-on items, passport scanning and a final station where you turn in your customs declaration form and receipt from the passport scan), but at 45 minutes all told it was better than the up to 2 hours it can take now at Logan Airport in Boston. 
3. The Airbnb experience was fantastic. I was a bit wary of staying in the home of people I didn't know, but with my room a bit removed from the rest of the house (I was over the garden extension) and my own bathroom, it was extremely comfortable. Traveling on my own, it felt nice to have people to talk to for a few minutes when I came in every evening. The location was ideal -- I really like Queen's Park and it was fun, after two years away, to explore new things in the area.
4. The 2GB add-on package I purchased for £15 with the sim card from EE was more than enough data for my stay, even running Google maps and the Citymapper app every day. I switched the phone to wifi-only data when I was in the flat and used a total of about .6GB of data over nine days. I could easily have gone with the 1GB package for a tenner. 
5. Having a smartie phone with me when I was out and about was certainly convenient for maps and transport info, but time spent looking at a screen is time not spent looking at what's around you, as tempting as it may be to check Facebook when riding the bus. 
6. The 90-day Art Pass for ten quid was brilliant. I got value for money within the first day of using it. They don't advertise the 90-day pass, but I saw a promo code for it in one of the London e-mail newsletters I receive (can't remember now which it was -- possible Open House or London Transport Museum). 
7. I need to upgrade my technology. Taking the bluetooth keyboard to use with my tablet wasn't worth the bother (heavy, awkward touch), so I finger-typed my blog posts on the tablet instead most of the time. Time to think about buying a Chromebook -- possibly the new Asus Chromebook Flip C101. 
8. Many years ago, my friend Helen declared me an honorary Londoner, but at the time I didn't feel that I'd fully earned the appellation. I'm chuffed to say that, finally, I think I wear it well. 

I came home with £20 in my wallet and ~£13 on my Oyster. Time to open a new spreadsheet and start adding things for the next trip to Blighty.