Packing
Less is better. Whether you are going to one country or four, you will enjoy the journey more if you have less to manage while traveling.
You don't need a fresh outfit & shoes for every day, you can re-wear & wash, and no one will notice or care if you wear the same shirt 5 times. You will want space to bring home things you buy so pack minimally and focus on the purpose of the trip instead.
Review the links below, leave behind anything you are not certain you will wear or use at least twice, and try to limit your luggage to what you can carry on the plane for the trip there. You can always check a bag on the way home if you bring home more than you took. 
Though we will have porters at each hotel to get your bags on & off the bus (we have a system!), you will need to personally carry your luggage through airports. Please be mindful that taking excess luggage will make this more difficult and likely slow down our group's timeline.