In my opinion (still looking for the other two 5-star-stages) a lot depends on the amount of climbing before Monte Bodone and Crans Montana. And by that I don't only mean the total altitude gain, but also the amount of climbing in the hour before the final climb, so that teams may be able to wear down the legs of some riders. What fears me a lot is the fact, that stage 13 might start in Ivrea (outside Val Aosta), so even without extra climbs in the Rhone valley the length of the stage is pretty descent. I hope you can follow geographically