I'm in agreement with Cyccommute 100% on this one, especially the suggested gearing ranges for various loads - they're too high in my opinion, at least for mountainous areas. Maybe if you're in your twenties and thirties and can push gears, but even then if you're not in excellent shape, you can go anaerobic pretty quickly and run out of gas after 30 minutes of climbing. I'm currently living in an area of the Philippines with extremely steep and long grades over 10% which I pedal fairly regularly on a road bike with a compact setup, 34-30 low (30gi). It's brutal in the heat and I can't imagine doing it with a load or long periods of time. At home I have a 34T mtb cassette and derailleur on my compact roadbike, that gets you to 27gi. Still not enough for touring.

The common solution for low gearing on touring bikes is the use of MTB cranksets, but there's an issue with that for some of us - the large Q-factor can cause knee pain. Most are 168 -175mm in width - an inch wider than typical road cranks, and too wide for some (ex-runner). I have two bikes here in SE Asia and the difference between the 146mm width of my compact double and 168mm of my SRAM MTB crank is night and day. Despite the obvious advantage of lower gearing on hills, the latter gives me pain (yes, bike fit is correct). I have found road triples like Shimano 105 (155mm Q) don't bother me, so that or the SRAM XX MTB crank (156mm Q) will be used on my next touring bike when I get back to the States. I had to sell a sweet Randonee due to the wide Q-factor MTB crank they used.