I just tried this out. Starting as a member of Iton Shetbeth puts you in the Hill of Workers, which is about half as far to travel as from as the starting point for the Watchful Rags.
On the downside, the entire region is choked with rivers that don't freeze at night so you have to swim, which causes a nasty attrition rate for companions. You can skirt around some of them, but there are so many that you eventually get boxed in and have no choice other than swimming. It's also tropical, which means alligators, mambas, and sundry other animals that you don't want anything to do with in Adventure Mode. The region around the starting point in the Nation of Thrones was also rather empty of animals large enough to be butchered so food is going to be a problem for a while unless you run across a herd of wild boars like my test dwarf did. Water isn't as there are streams everywhere.
Choices from there would seem to be: try to make it to the mountain range to the south with at least one companion in tow and skim alongside of it from there west to Silverysects or head to the sea to the northwest and swim across and then try to make it to another human civ in the region. I believe there is one that falls between the Lined Realm where uggi died and the Romantic Empire, which is at the foot of the Bronze Towers. The rivers don't freeze so the sea probably doesn't... hopefully. Freezing seas are absolutely brutal on adventurers thanks to the way that ice walls spring up from the surface during the night.