Do you use 5D III plus 24-105 as travel camera?

I have travelled to many different areas with my MKIII and the 24-105. At first i had the same concerns that you are having. I would often bring along another longer zoom until i realized that it would mostly be dead weight as it stayed in the bag more often than not.  For me it turned out that the MKIII and 24-105 is a very good combination and that i was always able to work within that focal range.