I think that you will be fine with either for both cities and landscapes. I would probably choose the 24-105, just from the point of having a bit more focal length to play with.
How about a good pocket P&S also? Not much weight and could extend your focal range. The 50X Canon PS SX50 HS gives good IQ and tremendous super telephoto range.
Post some photos when you get back.
I have a Sony RX100 which I'll let one of my daughter use. Will definitely take lots of photo and post some here. Can't wait for the trip to begin.