In reply to ksjs:
Taking into account "reasonable terrain (no scree), clear and signed paths ideally......relatively easy angled to get to the bottom of the gorge".
A gorge walk, 'there and back' though the tunnels (take head-torch) from Point Sublime end is fine (we did it with a bunch of 3-7 year olds), but further downstream there are exposed sections with ladders that may not be to their taste....(my wife ran from Chalet CAF de la Maline to Point Sublime along the gorge path and said the ladders were surprisingly exposed).
I did a fair bit of great mountain biking along GR routes in the general area and there will be tons of great walking to be had (and NOBODY on them).
Castellane would be a good place to base themselves near (bigger & nicer than La Palud).