Jephi did an extensive post on this subject.
I've travelled through deserts and very remote areas a lot myself as well, and would like to put in my 2 cents:
- Yes,
dust is the name of the game.
Make sure to protect the camera, also IN the cars. You need a good bag.
Putting a cloth on top of the camera out of the bag (I'd use my flex hat) is a good starter.
Dust will get in everything...
Take wet napkins with you for cleaning yourself and your equipment.
- No, a grip
IS a good idea. I don't know how and where you are travelling, but
THE biggest issue in some areas can be electricity.
Old cars with broken cigar ligthers, no power in camps, towns, places for most of the day etc.
The grip with 6xAA has been a live saver for me a few times...
- I cannot comment on the 18-135mm, don't have it. Should work in 80% of cases.
However, landscapes, narrow old buildings, bazars, etc need wider angles.
For wildlife on the other hand 135 is by far not long enough. I'd bring 2 extra lenses: 10-20mm Sigma & DA 55-300mm.
- Make sure to bring repellent and something for the children you'll meet. Giving money is for many reasons a bad idea. We bring a large bag of balloons and pens and the like. If you want to take a picture, you'll have something to give.
- Bring some extra money and (if you have the space) some goods to donate to local schools, medical support etc.
Remember Phill Collins' song "Another day in paradise"...
Have a good trip!
- Bert