We used it as an out of season night stop a couple of years ago and not surprsingly found it very quiet. We were directed to a pitch on the lower level of the site and this was at the bottom of a very steep hill. The ground was a little boggy and the facilities were 'tired'. However, we has a good meal in the restaurant and the reception staff were friendly and helpful.
The lake complex looked like great fun but was not in use at the time of our visit. In season, I imagine it would be a lively area and one to avoid if seeking peace and quiet.
We called in on our way north from the Pyrenees and were meandering back towards Caen, so did not experience the fastest route from Calais. To complete it in 10 hours, you will need to use the autoroutes, either via Bordeaux and then the A62 or the Rouen, Chartres Orlean, A71 and the A20 but the final appraoch will be over slow N roads. With children to amuse, it is a site worth considering.