Hadn't seen your posts about your trip, sounds neat. The sutra is a good solid bike, you should be able to change out the 28t granny to a 24 with no issues at all (most likely wont even have to touch the FD) This is a very easy and cheap way to get your gearing lower.
Re year weight, it will only come with trying out your list , but try to keep the weight down. Given the colder temps you'll be riding in, you will have to have warm tops and bottoms (fleece stuff perhaps) and good rain gear that can double as wind shells, jacket and pants. Being wet in cool temps really sucks, and layering stuff under good rain jacket and pants is very flexible for diff temps.

When are you thinking of doing the trip?