Exile Island by Konsumterra can be used almost 'as is' for a nice bit of old school hexcrawling off the Umathelan coast!
Let us have a look at all the nice details about Exile Island (aslo called Forbidden Island). Apparently, it used to be part of an empire; it is about 150km × 250km; it is a tropical island; it is covered with rainforest... So basically everything about this island: the history of the place, its size, its climate, its vegetation, makes is a perfect addition to any Second Age Umathelan campaign game!
Let's look at the reasons why the PCs should end up hexcrawling on it:
☠ The PCs could be stranded on the island because their ship sunk: survival game!
☠ The PCs could be on a mission for the ruler of one of the coastal cities: exploration game!
☠ The PCs could be looking for God Learner ruins in order to loot them: plunder game!