What are the effects of using CompleteQuest console command to cheat completing quests?

Question

I've got a problem with my savefiles and lost about one to two hours of gameplay. During this time I travelled to the children village little Lamplight and made my way to the vault, I think it's number 87.

While I found the quests to be very interesting, I'm not keen on repeating them and would like to skip this part of the main quest using cheat codes. Here's what I found: If you type CompleteQuest in the console, the current quest is completed. I would try this right now but unfortunately I'm currently immersed in a sidequest and need to finish that first.

Therefore I would like to know if you can tell me the results of using this cheat.

• What happens to the places I should have visited but now never travelled to? Will Little Lamplight be marked on my map?
• What happens to characters that are important for the quests? Will the children know me, when I eventually "return" to little Lamplight? Will the slave-keeping raiders that should have been killed in order to free those two children be dead?

Answer 1

The completequest console command only marks the quest as completed. The only things that will change in the world are things that are scripted to look at exactly that game variable, which is actually unusual for scripts to do. Quests usually consist of a small-to-large number of quest variables in addition to the "quest stage" variable – completequest doesn't touch anything but the quest stage variable, while most in-world changes trigger off of the various other quest variables that are used to coordinate game events.

It depends on how the Little Lamplight quests are written, but it's highly likely that either nothing useful will change, or (more likely still) things will change in such a way that it will break the area, its characters, and/or any later quests that chain off those quests. Using the completequest console command is almost always a bad idea unless you are intimately familiar with how a given quest is coded, or it's well-documented that completequest works harmlessly on that quest. It will definitely not mark Little Lamplight on your map, as that's an independent set of variables from the quest variables.

Fortunately, according to the Fallout Wikia article on Little Lamplight, all of the quests there are side quests, so you can safely ignore the children's plight and heartlessly proceed with the main quest.