I have just come back from a motorcycle trip in the western Himalaya.
I took my 550D, spare batteries and cards, 17-85 and a nifty fifty. Might be wise to leave the big zoom at home. you'd be better getting the 10-22 wide angle tbh.
It can get very wet and dusty, so take a lens cleaning kit if you can.
Defo get a polorising filter, this will get you good deep blue skys.
pack your gear in a good padded bag or rucksack.
A few of my images can be seen here
Have fun, it's an awesome place