If you enjoy siteseeing and relaxing, I would back up the recommendation made by longcol (above) ... the Loire valley is full of amazing chateaux, fantatstic son et lumiere shows, wonderful walks, lots of towns and villages, the famous Apocalypse tapestries at Angers and so much more.
The suggested campsite has been raved about by many on this site ... see reviews section ... and you can walk into Azay for cafes/bars/restaurants/chateau etc.
However ... what we usually do is to have about three different areas (all of which would be of interest ... and some campsites at each), then we wait until we are on the ferry (literally) ... do a weather check, and let that make the final decision as to where we go.
There are so many campsites in France that it is rare not to be able to find one to take you. The disadvantage of booking ahead is that, should the weather be poor, you are stuck with it ... half the bonus of camping is the ability to be nomadic and chase the sun ... or, at least ... avoid the rain/storms.
Don't forget to leave a review of the French and other European campsites you have visited!
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.