Well done , enjoyed reading your reports, glad I’ve not been doing a long distance walk in this heat!
Can agree with most of your points having done 6 LDWs ( and I’m probably still learning!).
My other half does all the booking as he’s retired but I check and double check first.
Never a good idea to rely entirely on a guidebook.
Training, I sympathise, as I live in flat Suffolk and it’s a good 3.5 hours to get to the nearest decent hills in the Peak district. We start several months ahead doing short walks and building up to both Saturday and Sunday, carrying our packs and increasing weight ( we B&B), until a couple of weeks before the LDW we walk 2 consecutive days of a couple of miles more than we would be doing at the start of the walk ( to sort of allow for the hills). We also try and have a weekend in the Peak district a few weeks before. Also just try and keep generally fit. I did have the idea once when I went to the gym of setting the treadmill on its steepest setting and just keep walking on it for ages!
That lasted about ten minutes until I got bored! We do have a road hill near here so I did keep going up and down that quite a few times, I figured that anything helped!