We stayed for a week at camping de l'amitié at St Laurent Nouan, a few km from Chambord. The campsite was ok, nothing special. Quiet and pleasant enough.
The best thing we discovered after a very expensive and disappointing visit to the chateau is the vast park that surrounds it. Access if free, they provide free maps and there are miles and miles of cycle tracks and walking paths that no-one seems to bother with at all. There is forest, views, lakes.....all peaceful and beautifully maintained. If you're in the area, it's well worth a day out with a picnic.

Good to know. It's worth a visit just for the park and fab views.