My players characters are stranded on Tython, having been duped by force illusions (partly caused by the mad Jedi master Ilum) into losing their ship and getting separated from their non-force-wielding comrades, who are much more suspectible to the dangers of Tython's vergencies (though exactly how, I don't know, grateful for ideas).

Right now, they're fighting Flesh Raiders, the only native sentients on the planet, and exploring the remains of Ilum's failed Jedi expedition that led one padawan to be enslaved by the Flesh Raiders, and the rest to their deaths. Ultimately, they'll have to find Ilum, who has been in a meditative trance for a decade inside one of Tythons ruined temples, find their ship and rescue their comrades from whatever troubles they've gotten in.

But I want them to explore more of Tython. How do I make this interesting, when there's no other people on the planet? Some of the PCs really wants to become jedi knights, so by dropping some info on them, I could easily cause them to try and quest through several of the ruined temples in order to gain insight, and maybe even be named Jedi knights by some ghosts within the force.

Rules-wise, in Force Nexuses, meditating in the temples of Tython gives a discount on buying new basic Force Powers. That's well and good. But I need some more. I need some danger and excitement, and some more tangible rewards if the PCs struggle to find several of the temples, but because they're so unimaginably old, little physical objects should remain.

What can I come up with? An extremely dangerous Terentatek might have made it's lair in one of the temples, and I could design some Sith phantasms or force-attuned monstrous creatures to stalk some other. Flesh Raiders might be camping out in one of the temples, subconsciously making use of its Force vergency, and having kidnapped some of the PC's comrades. Illusion-driven Force Trials of some sort is another option; one PC really really needs an illusory confrontation with his mother, who was a jedi knight and then abandoned him. Maybe a trial with some chasm that needs to be crossed, or three doors where only one can be opened, and the other two hide som terrible danger? What would you do? Have you come up with some interesting Force Trials in your campaigns?

And what rewards could I give, except for the obvious ones (force power discounts and lightsaber crystals). One of the PCs is a mechanic, so I have an idea of letting her seek out the forge temple, Vur Tepe, where she can get a huge bonus on anything she tries to craft. Ancient armor or artifacts, hidden away and preserved throughout the millennia in some deep, deep vaults? I don't wanna go over the top of course, not heap rewards upon the players, but they should get -something- cool for their huge troubles, because I've made, and am gonna make, Tython a really tough and dangerous challenge for them.

I'll be grateful for any ideas, no matter how random!

I don't know if any of your players are Seeker type characters. But there's a huge potential for force sensitive animals for the party to interact with. The potential to not only befriend, but maybe even bring some back. You could even give them a way to create star charts for Tython, so they can come back whenever they want, or potentially share its location.

A Force vision appears. It's an old man in Jedi robes beckoning you to follow him to a Temple. The ceilings are high and the halls are long. As you follow the old man, you can hear echoes through the Force of those who had occupied the Temple millennia ago. The old man stops before an open doorway and says "The Breath of Life begins here. Beyond that is the Code of the Jedi. And beyond that is the Path of the Jedi."