Okay, so I think I figured it out. You can be sent to two different camps. But if one is destroyed and you still have the quest, you won't be able to turn it in, because Illidan/Alleria won't be there anymore (and you will see only some dead bats lying around). You can still go to another camp that is up and return later to get this one.
If you abandoned the quest, while the camp is dead or about to be destroyed (1 min warning given), you won't be able to hand in the quest, thus the game will not offer it again if you abandon it. Don't worry, the quest will be offered again and can be handed in when the camp is up again.
Basically the camp can be "active", it can be "destroyed" or it is "about to be destroyed" (with a 1min warning given).
Prequest Securing a Foothold
Followup Sizing Up The Opposition
Camp 1: Reinforce Light's Purchase
Camp 2: Reinforce the Veiled Den
ORIGINAL POST
This seems to be a breadcrumb quest (as they usually are with go find NPC x somewhere else quests), that is supposed to bring you to another quest hub / story line. But if you already completed the followup Sizing Up The Opposition You won't be able and you don't actually need to do this quest anymore. Simply move on :)
You can check if you completed the followup with this script: /run print(IsQuestFlaggedCompleted(47473))
Edit 1: It does give you a flight path though, so not sure what's up with that and how to get it. When I moved to the camp there were no NPCs only dead bats on the ground
Edit 2: I realized that the camps seem to be randomized and destroyed every now and then. If the camp is destroyed and you did not hand in the quest in time, you should be able to pick it up later again, when the camp is back up and not dead.
Edit 3: Added info from response by FlowXL below regarding the 1 min timer