In reply to ChrisJD:
That time of year you'll probably need to book in advance, since that site seems very popular in the summer. I tend to prefer more remote camping with fewer facilities but other people I know with families seem to rate the site highly.
In terms of location you couldn't really do much better in August, as it's just a few km from Tarascon, very close to great shady limestone on both sides of the valley, not far from shady granite further up the valley, and very handy for other fun stuff like show caves, canyoning and horse-riding.
Many of the crags are kid-friendly enough, given the obvious limitations of being natural rock on hillsides. The initial sectors of Alliat are within walking distance and should be fine, as is Sibada on the other side of the valley. Up at Auzat the right hand sector is very popular with families. Plenty of other options too. Bouldering just a few km away at Laramade is kid-friendly at the bottom, on the good boulders in the meadow, but gets much steeper further back. The other good bouldering is at Orlu, half an hour or so away, which is a nice place for families too.