I did more exploring around the Buried Sea area today, as there’s a bit more to it than I thought. There was a camp of fire goblins on Suncrest Isle that was pretty good xp, where I’ll probably spend my double-xp periods from now on, and I found some chests along the beach on another island, in which I found:

It also turned out that I could enter the city of Katta Castrum by jumping into the big whirlpool at the center of the zone. It’s an enormous city, divided into outer areas under siege by elementals and Shissar and the inner area where the old Combine empire lives, but it’s largely empty.

I picked up a handful of tasks and did a few of them that I could do right within the city itself, but none of them were all that important. Katta Castrum has its own separate currency, but to pick up any of those it looks like I have to do the harder, group quests. I doubt there’s anything I really want to earn here though, since it would probably be quickly obsoleted once I reach the Seeds of Destruction areas.