A few helpful hints about this quest.
First and foremost, yes it is going to be hard to see. The easiest way (and it's not going to be great) is to zoom OUT as much as possible. You'll see a lot of giant and little else, but that's the best it gets.
Second, part of this quest is to kill 100 scourge. Do NOT go looking for scourge to complete this part, trust me, they will find you. Find Algar and the Prince first, and kill them, you will kill plenty of scourge along the way, and during the fights, and after the fights...
Third! This one is really important! <Gymer need Stormcloud!> This frustrated the hell out of me during this quest, because I could find the stormcloud, i clicked it, I right-clicked it, I clicked it multiple times, I stood in it, around it...nothing would heal me. If you'll look down at your new action bar you have 4 abilities, an earthquake looking button that does AoE damage, a redish button that does an AoE knockback +damage, a bloody hand that picks up Vargyl and picks up stormclouds to heal yourself and then another hand that throws a Vargyl if that's what you're holding.
So Click the stormcloud, then click the bloody hand. It will heal almost your full health (depending on what level you're at when you click it of course)
Fourth, as best as possible, run along roads. Your aggro radius is ridiculous, as a hunter I could see the armies of undead running towards me and it isn't pretty.Every now and then, stop and kill them all. Otherwise they will keep following you, right up to the bosses and then you're fighting 300 undead plus the boss. There is a way to kind of reset them and leave combat! There is a ramp at [30.78, 66.63] that leads up to the argent strand, run up there, and around the corner to the left. Go a few paces and stop, very few undead will follow you up there! You can kill them. And then, look down and you can see the Prince! Jump down (no fall damage!) and you won't catch any extra adds :D
The Prince Nevarius fight. PAY ATTENTION, he does a soul reflection spell, it shows up in yellow across your screen, it shows up as a debuff, AND it shows up as a channeled spell under his name plate! STOP DPS during this spell! You AREN'T HURTING HIM! You will be reflecting all that damage onto yourself!
After you kill him, quickly look for a stormcloud, but don't go far! Thyrm will appear then and if you run away you'll have to kill the Prince again to spawn Thyrm.
Lastly, for some reason, he doesn't auto attack after you do a damaging spell. You have to hit your "T" button, or right click your target. This will add so much more damage, and make the fights so much easier!