Eastern France + Switzerland Travel Lens

[Tounis]

I've been a bit busy lately and didn't have much time to contribute to the forum. I took most of my latest pictures with the 16-35 f/4 mainly because it was new, I was in a rush and I had no time to use more than one lens. It's a great lens but having only an UWA would be too limiting. The 70-200 could be useful too in the mountains, and the f/4 version isn't too big. I usually always take it when I go hiking. The 24-105 is a safe bet, and as others said, with the low light abilities of the 6D, you should be fine.
I like your choices for Switzerland. The last part of the Glacier Express between Chur and St. Moritz is a little wonder of 19th century railroad building, and part of the UNESCO world heritage list. Engadin is a great place too, as are Lugano and the lake Como. You shouldn't be disappointed.

Edit : By the way Stephen, I'm looking forward to seeing some pictures you took in Switzerland. I hope you had a nice trip.