The letter I found from 27 days ago said "1200 gold per 1000 bushels"--of course, you have to actually get the food to Nightmarch. I have enough trouble just traveling Paisly-Madina-Fissoa.
Out of curiosity, can bandits attack you while traveling? At sea? I've never had a bandit attack me and take my gold, and I've wondered if that was because of my sea route.
