Hi Geoff. If you go to ACSI website, go tomeuro campings then theme, then "see more" click on small site you will find lots of small sites. Municiples sites in France, in most town and vilages are good but I tend to get there just after lunch to get a space. So that you can find another before dark, never book nowadays, but used to it now.
Hutch.
Google the town near where you want to stay. You will usually get the municipal website, on which you can look for camping, and then down the list. Some websites will offer English text, but if you use Google chrome you can get it to translate - some times not 100% accurate but generally pretty good.