The road looks pretty steep with several wide hairpin bends. Having driven from Annacey to Chaminox, not towing. I don't think I would like to do that trip. Cluses to Taninges, although there are caravans at the site.
You might be better to go to Galliard and then the 907 to Taninges.
What are van and what are you towing with. ,?