I think I have reached a new balance point. Dropbox has been emptied of everything meaningful. The source files for this site reside on Icloud drive, and each computer has had its build command updated to read files from there and output the results to a non-synced folder.
Very nice.
A little bit of extra care may still be required as Icloud drive is not quite as aggressive (by default, at least) about keeping files downloaded as I had set Dropbox to be. It was nice and quick to force the folder to download before I performed a build, but it would be good to know if that is something I will have to keep thinking about. I am completely fine to have most other things download as needed, but my site I would like to always have available.
Apart from that problem of not having been downloaded, reading files from a folder on iCloud drive using a Python script was happily not a problem at all. It only struck me well into the migration process that iCloud drive could very well have some kind of completely outrageous path behind the scenes, and/or be heavily sandboxed from lowly, untrustworthy things such as user created scripts. I was very happy to be wrong there, the path was both reasonable and stable, and the script ran without a hitch from the very first time.
(What would I have done otherwise? Worst case, I guess I would have copied files around manually. Or even started keeping the site in a git repository instead. But Apple tend to make things like this possible, even if the solutions can feel really obscure before you find them, so I am pretty confident it would still have worked out in the end. The process may have involved permission dances and aliases or something though …)
Summer holidays are coming up in - relatively speaking - the blink of an eye. I somehow feel as if they have started already, I will just for some odd but perfectly normal reason spend the first few days in touch with people at work … ?