Plot a route that takes you over the Gt. St. Bernard Pass, Little St. Bernard Pass, Col de I'Iseran, Col Du Galibier, through Briancon, over the Col de la Bonette and then follow the D64, D641, D2205, D6202 to Castellane and then take the D71 along the Gorges du Verdon.
For your return trip, I'd advise a route over Mont Ventoux.
It would have been helpful if you'd given the location you're headed for in Provence.
