So what exactly does “Trekking in the Baliem Valley” mean, and what does it look like? Just a snap shot here, to put an image in your mind of what this is, which is the context for everything that follows:
Trekking in the Baliem Valley, as used here, means multi-day, village-to-village hiking along traditional footpaths established and used by local people in the Baliem Valley. There is no electricity, no phones, no commercial development, and no combustion engines (i.e., no vehicles of any kind). Similar to a wilderness backpacking trip, you carry everything you need, including the majority of your food. Accommodation in villages is basic, and can be described as a “homestay” where you are staying with local families in their dwellings. The general area is sparsely populated, with small villages distributed hours apart, with little to no human development in between. The terrain is steep and mountainous, with most days involving climbs, descents, and river crossings.
Word to the wise: I would describe unguided Trekking in the Baliem Valley as “adventurous”, and requiring good gear, reasonable fitness, and experience to enjoy as an unguided trip. If you are an experienced wilderness backpacker, you'll have fun. If this is your first time carrying a pack, might want to rethink it, or at least make sure you are with someone who has done this kind of stuff before.