Route Advice Please

[Sable]

I should be grateful for advice on a route from Vallon Pont d'Arc across to the A20 going north to Souillac. I have gone on most of the north/south routes, even those that look a bit dodgy for m/homes but not east/west as far as | can remember. An old autoroute suggested going via C-Ferrand but this is a very long way round. From Souillac I would be heading across to Chalon-sur-Saone, Nothing really narrow or too steep please as no co-pilot and a 3.2m height van! Thanks in anticipation.