Planning Mansarovar in 2010. Anybody been there before? How is this for an itinerary?

15 Days: Kathmandu – Nyalam 3750 m>Dongba.>Mansarovar 4558 m >Mansarovar Parikrama - Darchen>Darchen – Tarboche – Dirapuk ( 4860 m )>Zuthulpuk ( 4760 m )>Darchen>Dongba>Nyalam>Kathmandu