Trip to Tibet - what lens to bring

Fellow Nikonians,

I would appreciate any suggestions on the lens(es) I should be bringing for my trip to Tibet (in May 2012).

We'll be doing a lot of hiking and definitely plan on visiting the famous Potala Palace.

My current gears are as follow:
Nikon D700
Nikon 24-70 mm f2.8
Nikon 50 mm f1.4D
Nikon 24 mm f2.8D
Nikon micro 200 mm f4
Nikon SB 700
Sirui and Gitzo Tripod
Sirui Monopod

Thinking about investing in 85mm f1.4G (some folks say the 85 mm f1.8G is 'good enough') and/or 14-24 mm f2.8 and/or 70-200 mm VR II.

Any advise on what to 'experience' or expect while in Tibet are very much appreciated.

Thank you all !!