On a far briefer trip to Italy, I took the X100s and the M-D 262/ZM 50. All-day M-toting takes a toll on my neck and shoulders, so it was a relief and a pleasure some days to use the far lighter Xcam. (On days I carried both, I could also consult the X100 screen to help determine M-D exposures. This won’t be an issue for you.)
I might proceed differently now—a Leica T instead of the X100s, to be able to use lightweight T lenses (23, 18-56), as well as mount small 50 and 21 M lenses.
Have a great journey. Don’t overpack!