we stayed here a coupe of years ago in the whitsun week (I am assuming that is when you want to go)
It was simply the BEST campsite I have ever been to, my kids still ask to go back (They were 4 and 6 at the time)
The pool area is good, a couple of slides, a huge jacuzzi that all the kids played in, and enough loungers at that time of year. The parc itself was spotless, clean loos/showers, small shop, small bar/restaurant (We never used it though)
Best of all it was about a 10 min cycle (if that) to the grounds of the Chateayu de Chambord. There is a wild animal park we saw baby wild boars etc from forest hideouts (they have little veiwing places around). They have a huge chateau, a little like Disney on Acid with 365 chimneys. At the Chateu there are a couple of little restauants too. There is a horse show, the kids LOVED this and also boats to hire, another fun afternoon activity.
We also went on longer cycle rides along the river and beyond which were fun.
Blois is a pretty town, 30km away, and it has a fab night illumiation show (OK kids were up until 11pm or later) in English at least once a week, which shows the history of the place.
We went with Eurocamp and the kids loved kids camp for a couple of sessions, DD1 also learnt to bike ride there, no traffic and wide smooth paths. The central area has a green play area where kids played together with bats/ball and also on the climbing frames etc. No tent/mobile is more than a minutes walk away so our kids were able to play there until late in the eves (9pm) with others.
It is dirt cheap to go on your own steam or hire one of their chalets, but at that time if year eurocamp/keycamp is approx £300 for the week. Therefore we used them!
Serously my children have been asking to go back every year so far!!