The Southeast Asian traveler’s route is so popular and well established that it has a nickname: the Banana Pancake Trail. The classic itinerary is a loop that starts in Bangkok, crosses northern Thailand, passes through Laos, travels through Vietnam from north to south, ends in Cambodia and then returns to Bangkok. This trip can be done entirely by bus and train, without ever taking a plane.
It is also popular to start in Singapore, cross Malaysia, visit the southern islands of Thailand and then reach Bangkok. For itineraries of several months, some also add some islands in Indonesia…