Personally I might put my stronghold in the Spine or somewhere in Du Weldanvarden.
They are capable of cleaning up radiation but to cleanse an entire island in a decade, or 100 years, you do know that Vroengard is much larger than Ilirea right? If they could cleanse an area the size of Du Weldenvarden in a year with the limits in place, then I would agree.
We can at least agree that its possible to remove the radiation from Vroengard, we just don't agree on the amount of time it would take.
The reason they can't use Vroengard is because there's a lot more magic there than just the radiation left by Thuviel. Since some of that magic was undoubtedly wrought by dragons, or perhaps without the ability to speak, it would be impossible to remove it all using the name of names since not all of it was bound to the ancient language. The remaining magic after the battle on Doru Araeba is substantial, not to mention the radiation has had a century to permeate the entire island. It's created dangerous and unpredictable species, left a myriad of potential traps, not to mention the mysterious people who have already settled there. It's a much bigger job with many more potential dangers than just the radiation left from Galby's death. In Ilirea, they were able to act quickly to contain the radiation before it spread by sealing the citadel, thus making it much easier to deal with. And even though Eragon had plenty of spells to undo afterwards, it's still nothing compared to the magic cast during a battle with harmful intent. Most of Galby's spells in Uru'baen were to protect himself or his followers, not cause horrific deaths and destruction.
I still don't see why he didn't use the mountains in the Hadarac Desert. You can use magic to grow food for the Riders, create fertile fields to raise livestock for the dragons, and create defenses at the peaks of the mountains. With the Eldunari you could make unscalable cliffs. It was already shown that you can make things grow with magic that wouldn't normally survive in that climate. It's isolated enough from all the races, not to mention any attacking army would have to survive for days marching across a freaking desert.
It’d be a titanic drain; Elves as an entire race can make Du Weldenvarden stronger, but they don’t raise mountains. The land of Du Weldenvarden is suitable for forest and so the growth is partly natural. A desert is not suitable for that kind of farm life, and you’d constantly have to battle to keep it alive. Remember that magic comes from energy which comes from food, so if you have to use magic to make all your food then you have a serious problem. The dragons would necessarily have to hunt in the nearby Beors or Du Weldenvarden.
Plus, making a desert habitable is no where near what cleaning up a bit of radiation would entail, which lore indicates is not difficult to clean up. Even the Eldunarí could not so reshape the land, or you’d have seen Galbatorix doing it.
All good points.
It would certainly take a very, very long time to make Vroengard inhabitable again so long that it raises the question of whether it is worthwhile.
So I think Du Weldenvarden is a good, choice. Thats where I'd put it. For several reasons, one its in Alegasia, two its heavily protected so its a safe place, and three its close to the elves who are the most dedicated to the preservation of the dragons.
But Vroengard would work too, once Doru Areba has been rebuilt and all the radiation removed.
I just do not think that Du Weldenvarden should be dismissed, solely due to influence by elves.
But I also think there should be multiple Rider Strongholds. So no one can be over thrown.
There are also Beirland, Illium, Uden and Parlim as well. Those could be locations for Rider Outposts or Strongholds.
Also Paolini said on Paolini.net that Eragon felt that he would have been too powerful a force to end up on Vroengard or something like that.
What do you think?