This trek is quite similar to the Darcha-Padum (9 days) trek.

If you go the short way from Darcha to Padum it takes you 5 days (1 pass) to Purne.
If you prefer the longer way to Padum it takes you 7 days to Purne. You have to climb two passes (4.890 m, 5.450 m) instead of one pass (5.000 m).
In Purne you meet the short way to Padum. It is possible to make the side trip to the Phuktal monestary.

From Purne to Padum see the other description.