On a long trip especially on a hot climates you must consider "longetivity" of the films, especially after you've shot them.
I've traveled for years on a motorcycle and often 120 roll films with me staying unexposed or exposed for many months at the time, from ferocious heat to freezing cold, wet humid, dusty & sandy.
I wasn't so impressed with C41 films, but Kodak Portra series seem to do fine, Pro 160C also came out very good after many months of abuse.
Kodak E6 films weren't so impressive - I've gotten them back with color casts and shifts after development. I've found Velvia 50 ranks among the most "resistant" color films, almost never had a problem. The new Velvia 100 is acceptible as well. Provia 400X does fairly good while Provia 100F is more prone for "heat-treatment" (maybe because it's an older emulsion?) - loss of contrast and cast.
In any case, other than the mechanical damages, I've found the most critical is the quick temperature changes and condensation that abuses the film. You must really take care not to let them change temperature quickly, i.e. going quickly from desert up to high mountains or vice versa, throwing them into freezer every day in-out in tropical climates etc - don't do it or avoid as much as you can.
When taken care of color film is quite capable doing long journeys on harsh climates.
