Great writeup. Lots of useful info & details. Well done! (I found the situation with the tubeless tyres particularly interesting).
France on a bike is a totally different proposition to France by any other means of transport - in a good way!
It can be pricey - but it's all relative. I've cycled rural areas in Germany where villages have no shops at all. After 3 or 4 with no facilities France and its €3 cokes becomes more attractive
.
However, I do recall rolling into a campsite in the southwest of France and being declined. Before I could work up some righteous indignation, the campsite operator explained that they were very expensive and pointed out a couple of places within a short distance that would probably suit me better. In hindsight I prefer to think that he was being helpful rather than avoiding lowering the tone of his campsite
. In fairness, the next place was half his price.