A few things that I’ve come to see as essential for any trip from 1 week to 1 year:

Mesh Travel Bags  (I really like Muji and Eagle Creek’s lightweight bags)
Travel Alarm Clock (pull it out and any hotel room will feel more like home)
Probiotics (double check with your travel doctor, but these help to keep me feeling OK until I get used to the food)
Swiss Army Knife (just make sure to check it!)
Small Medical Kit (Band-Aids and ibprofen)
Large Scarf (for the girls – chilly nights or Catholic churches)
Small Point-and-Shoot Camera (I love my Lumix DMC-LX5)

And in case you’re not staying at the Hyatt or might unexpectedly find yourself on an overnight train, think about including:

Lightweight Silk or Silk/Cotton Sleep Sheet (doubles as an extra blanket)
Headlamp (for when the power goes out for “just a minute madam”)
All Terrain Sandals (good for shared showers and spontaneous riverside treks)
Mid size microfiber towel (large enough to cover yourself if you have to scurry from that shared shower)
Water Purification Tablets (read “Trek” and you’ll understand)
10’ Nylon Rope (for hanging laundry or escaping from a burning building)
Earplugs (because even if they say the bus doesn’t play music, it probably does)