Lake Andaram Central.
One Tier IV settlement is the Velothi style Aimrah in the pensinsula in the north.
Aimrah has a Silt Strider port and a docking area (no actual boat travel, it's all freighters here). It is house Indoril's primary trading outpost on Lake Andaram (importing a lot of saltrice from the Deshaan), so the docking area needs to be prominent while the actual living quarters may be made up of hostels, with very few inhabitants that are not dock workers or travel agents.
Aside from the prominent harbour in Aimrah, it should have large accommodations for pack guars to take the saltrice inland. As the settlement is Velothi, it should have very few shops if any, rather having communal service structures such as a large tradehouse, probably a temple or at least shrine of some sort, and probably at most one or two outside merchant stalls.
Lake Andaram should have an abundance of grottos and other hideouts, maybe some ruins close to the land; that is largely up to the claimant, although the south-western land should have one or two Daedric ruins, one near the lake line, partially submerged.
It's a sweet water lake, so inhabited mostly by mudcrabs, fish and slaughterfish. There is possibly organised underwater activity hiding in its depth. We might want to add submerged pirates with water breathing potions eventually. Their hideout should be well hidden but accessible, since this is one of the most patrolled lakes.