you may not necessarily need anything special...in terms of gearing...
for where you're going. sure, you're going to places with some really
high mountains, but you're not going to be climbing sheer rock faces.
you're going to be on paved roads mainly, and those are "generally"
designed for motor vehicles.

depends on what routes you'll be taking. riding paved roads up and
down the valleys, or trying to cross ridges on dirt trails?

check the crazy guy blogs. lots of folks post their gear list on the
first page, with details on their bike's gearing. then the daily blogs
will describe the roads and terrain.

42/32/22 with a 34 in back should be suitable for most of your ride.
be prepared to push or throw bike in back of an oxcart if needed.