I did this route last June 2005 from Savine-le Lac to Briancon, then over the Col de Galibier and down to Annecy. Cavine-Le Lac to Briancon was dogged by heavy trucks, but onward towards Grenoble, and over the Col de Galibier was fantastic. Excellent road surface, good visibility, sweepers through to first gear hairpins, this route has it all. Oh, and make sure you do plenty of press ups before tackling the Col de Galibier, going down is going to tax you every time you hit the front brake! I can recommend "Les Chaumettes" Hotel at Savines-le Lac. Very biker friendly, and a wonderful place to rest. Ciao. Mahout.
Mainly main road route on the N94 with mostly open road and easy overtaking, some decent scenery on the way down to Embrun and the lake at Serre-Poncon.