If you are going to project, I would use Kodak E100G or E100VS, also Fuji Velvia. All these films will project well, but do not expect the exact same results when scanned.
I assume that you will be bringing these films back home to process as this a long trip, people have mentioned X-ray scanners, I wouldn't worry about them unless you plan to bring films that are 800 speed or faster.
I will recommend that you use a processing house that will process, scan, and mount all at the same time, you will get far better results than if you try to scan later, or yourself. Unless you are lucky enough to live close to a place that does E-6 in house plan on about a two week wait for the photos to come back, and with the films I have mentioned above it will almost be like you are there again.
If you insist on using Kodak Elitechrome or Fuji Sensia, because of availability or cost, I would go with the Sensia. I want you to know that I will almost always pick a Kodak film over a Fuji film, but in the case of these two films Sensia would be the way to go.
Enjoy your trip.