In reply to wobblydave:
Musadriere is the most central campsite, but is quite pricey. The one in grez sur loing is cheaper, and has a range of other activities nesrby like kayaks etc, but is further out from the main areas (bit closer to elephant)
for kiddy friendly climing, theres loads of white kids circuits around the place, in particular at gorges d'apremont, near barbizon... head into the main street of barbizon, and keep going to the end where youll find a forest cafe and parking. Looking at the cafe, to the right a track leads through to some of the main climbing areas. A few hundred meters down this track on the right is a good area of low level kiddy boulder routes.
Another good area is the main trois pignons carpark. Follow the main track from the car park, and on he right a few 100m down are kiddy white boulders, as well as yellow, orange and red circuits offering a bit of progression.
Avoid bas cuvier as it covered in nasty rubbish and theres not that much at an easy level. Elephant wont be child friendly either.
Whenever I go there are buses of school children around, which tend to gravitate towards the kids circuits so if all else fails follow them!
Hth enjoy!