Welcome to Yali Country
Yali country is a great destination for more adventurous trekkers with enough time. You need about a week to walk there (the Yali themselves can do it, barefoot, in two days) and you should allow at least two or three days to explore once there. You might be able to get on a mission flight back to Wamena, but otherwise you’ll have to walk back or charter a plane. Villages with airstrips include Angguruk, Pronggoli, Kosarek and Welarek.
The most direct route runs from Sugokmo or Kurima to Ugem, then up the Mugi Valley, over 3500m-plus Gunung Elit with at least one night (but often two) camping, then down to Abiyangge, Piliam and Pronggoli in Yali country. There are sections of long, steep ascent, and the upper reaches over Gunung Elit involve climbing up and down several rustic wooden ladders. From Pronggoli to Angguruk, the biggest Yali village (with a large market twice a week), takes another one or two days.
An easier but longer option, about eight days from Sugokmo to Angguruk and still with plenty of up and down, is the southern loop via Wesagalep, Werima, Soba and Ninia.
Whichever route you take you should have an experienced guide. You should be able to organise one in Wamena.
Beyond Yali country it’s possible to trek southeastwards into the country of the Mek people, similarly small in stature to the Yali (their main village is Nalca), and even to cross Papua’s north–south watershed to Langda, the main village of the Una people (considered pygmies).