Carol,
We stayed at this site last year - Unfortunately for us it rained for 2 weeks in August....but don't let that put you off .... Summer weather in the Loire is normally very good (though not as guaranteed as the Med).
With an early Ferry crossing to Calais you'll easily get to this site by mid to late afternoon. (Motorway via Paris)
You'll love the site and be especially pleased with the Canvas Hols accommodation
There are loads of places to visit in the area (by car).
If you get Chateau'd out and zoo's are your cuppa - The one about an hour's drive eastwards is outstanding
Regards
Pete - Hemel Hempstead