I agree with you Vicrev, on the country side in France, finding to eat can be tricky.
I'm used to keep 1 or 2 pack of dry soup (excuse my English
) and a small amount of pasta in my backpack.
It's the emergency food which allow to survive a day without grocery or bar.
Another "good to know":
the small groceries are mostly open at Sunday, but closed at Monday
the super markets are mostly closed at Sunday, but opened at Monday
For the water, there is no problem:
1. Almost all villages have a cemetery: cemetary imply flowers, flowers need water!
So go around the churches you will find a tap...
2. If you don't success with point 1, have a look for an inhabited house, knock at the door and say that you are a pilgrim and need water.
I never have been refused a refueling of my bottle.
For the ATM's, they are quite easy to find: I don't remember to have not see one at least every 2nd day.
Bonne route, Jacques-D.