An area I overlooked off-camera was here. This is the lake Oradinar tells you about; you can catch fish here very easily. But it's also got two other things of note:
- A locked chest containing Grav and Corp runes, a pile of gold and a wand of Magic Arrow on a little island you can easily swim to. You can either lockpick it or break it open; I don't think it has a specific key.
- If you come in through the locked door near the 3F staircase (pick or smash it open; I don't think there's a key for it), you can follow the path south and east to find an enchanted chain mail armor of Missile Protection. Probably a better choice for characters with lower strength/carry weight (like me).