Erm... Film on long journeys
You shouldn't even complain if you have a fridge and a car. :)
I did over 3 year round the world journey visiting 5 continents on a motorcycle carring Pentax 67 with 3 lenses and around 30-50 rolls of 120 films at a time. Equipment and film went through hell - from desert to ice. My P67 camera that is as old as I am is tough as an ox - not a single problem during over 100 000 miles of third world roads, offroad trails and motorcycle vibrations. Sent the film back home with a trackable trustworthy services such as UPS, DHL, Fedex from the bigger cities I visited. It's was BLOODY expensive so I sent them home around twice or three times a year, not more. Also I bought new film stock around that frequency. Friend of mine developed them and scanned - put them online for me to download and keept the negs/positives archived there till I got back.
I found out many interesting things about films living in extremes per long time after being exposed:
B&W films can survive hell (except IR, which you need to take care). Some C41 color negs can do fairly well, but not so environment abuse resistant as B&Ws, Kodak seemed to be little better than Fuji C41s, but not much difference. Kodak's E6 films seemed to be the worst - color overtones when got heat treated in Australian +40C desert. Fuji Provia 100F - not so good, but still better than Kodak. Velvia 50 and 100 - seemed to be the best out of E6 films, colors didn't seem to be as affected after longer hot climate abuse both before and after exposing, also Provia 400X does fairly good.
This is no scientific method of course, since with motorcycle I was really affected by the climate and the film batches I had were very varying containing many different types of film with different expiry dates (mostly fresh though!), but I guess per average they showed their tendencies with the above "pushed to extreme test".
The worst factor seemed to be the quick and dramatic temperature variations: i.e. hot day and a freezing night and the condensation that comes with it. Or from hot plains you ride into freezing high mountain altitudes or down again. I'd be very careful with the fridge if you don't run it during the night off the battery, unless you have very well isolated fridge that has very slow temperature rise and drops between the cycles.
Safe roads and you'll sure love South-Am - one of my favourite continents to travel!