In reply to Woof Woof!: Army socks WILL last much longer than most of the others. However you feet will take more damage from them than from the more expensive pro versions and will be more prone to the various nasty bugs that can infect feet. If you aren't going to be doing much extreme terrain a get round for this is to wear light weight walking shoes (which are also less effort to break in which will be nice as you probably need to replace your foot wear a couple of times during the trip) however if you are going to be hitting more rough terrain I would personally recomend good quality walking socks combined with good boots. They really don't wear out very quickly.
Someone else will have to give you an opinion on the mohair ones though as I don't know anything about them.