This is what I was taking issue with: "Ask permission to send them a pre-charged battery and a charger." Which I assumed meant via post/shipment service and thus the need to meet the HazMat requirements. There are many scenarios that one could use to seed batteries and no doubt you and others have done or thought about the concept and it is a good idea overall especially for touring in your immediate area.Fair enough, but you didn't address the substance of my comment. My suggestion of seeding the route can take on two forms: either visiting the route itself in advance (dropping batteries off with people), or leave with a lot of batteries and drop them off as you go (leaving chargers as well, so that you can use them on the return trip).
I found your dismissal of the idea as impractical kind of strange when I reported that I had done it multiple times this summer. It could be as little as a single battery left in advance with a relative who lives along the anticipated route, and that alone could be a big boon to a trip.
Sorry for seeming argumentative, it was not my intention. I really like the idea of the routes you have done and hope to use your format myself next year. Particularly using Ferry systems here in the PNW/BC/AK to your advantage.