Apr 7, 2012 - 5:23 PM
You will have to count with at least 3 hours to reach the Eggishorn from Montreux and another 3 hours to go back. How much time you would like to be at the Eggishorn is hard to say: at what time do you want to leave Montreux, what will weather conditions be that day?
On a beautiful day, maybe you just want to enjoy being there and looking around. If you want to reach the summit of the Eggishorn you'll have to climb another 50 m. starting at an altitude of 2.870 m. There are no easy round walks as far as I know.
My suggestion would be, if weather conditions are good: don't hurrry, and leave Chateaux de Chillon for the next day.
I have no idea if on day 3 you'll have time enough to walk round Geneva.
I'm sure others might have different opinions. Nevertheless, I hope this helps!