I've been purposefully avoiding doing any of the Sanctuary Hills settlement requests/missions because I plan to use a mod that replaces the derelict version of Sanctuary Hills with the prewar pristine version.

But can this be done without interfering in the game?

When the mod is installed, will the NPCs currently occupying Sanctuary Hills still be present?

Or will they vanish, either because they are removed from the map or they're on the postwar map?

I assume if they are still there, I can still complete the requests as needed.

I'm assuming I'll have to make sure a Power Armor station, a Workshop and a Crafting Station are added, because these would not be present on the prewar map.

I am unsure, but I would like to issue you a word of caution.

Any mods you install pre-G.E.C.K. could potentially corrupt your savegame files. Use with extreme caution.

Don't worry, I have no intention of using mods that aren't created with G.E.C.K.

I'm just not certain they are all that stable.

And some of them mentioned needing to use console, which I know from experience isn't practical for a Steam player, because the moment you press ~ (console line parser), your Steam achievements are immediately disabled until you exit the game completely and restart it.

I just wanted to get an idea if this could be done.

Basically, just work through any problems I might encounter before getting the mod.

I'm uncertain if I can do it myself though, I experimented with making two mods for Fallout New Vegas and I couldn't get either of them started, let alone finished!

The limit of my skills is editing map objects.

For example, there's a massive gap in the wall on the New Vegas Strip map, I modded the wall so the gap wasn't there anymore.

Or I replaced one of the fridges in the Lucky 38 suite with a custom mod one.

Considering proper mod tools won't be out for some months yet (Q1 2016), I would just advise not worrying about it. Start a new game when you come back to the game later for a modded run and just play this one under the impression that mods will be minor and cosmetic.

Also as an aside, I expect one of the 'pristine' mods will just be an object swap for the houses that keeps the main structure, but swaps out the meshes with a repaired version after you complete a quest or pay some materials. It is unlikely this will cause any issues even if you have a built up area. Prior to that, there will almost certainly be a mod that turns the houses into scrappable objects, letting you remove them and replace them with anything you want, including an infinite array of modded in buildable pristine houses. That would certainly not interfere at all!

It depends on the mod... there are three classes of mods I've seen so far:

1) Simple asset swaps (mainly texture and sound): There is no problem with this. It won't corrupt anything.

2) Console command scripts: Basically text files you shove into the main folder and run from the console. The newer version of the settlement object bypass mod is like this. It would be unlikely this would corrupt anything, but you have to be aware of what it does. For instance, don't build so much that it kills your performance or crashes your game if you bypass object limit.

3) Mods created with Skyrim's tools and hacked over to Fo4: These can cause severe issues. Avoid them unless you're very sure of what you're doing! You'll know these mods because they'll have an esp file.

Since Settlements are a new feature to Bethesda games, I'm not sure how anyone would be able to answer this until a mod is made and applied to the game.

I would be very suspicious of any mods that modifies a settlement or does anything to workbench / station before the GECK releases as it's uncharted territory that will likely take a bit of experimentation to figure out even with the GECK.

I'm guessing that all these mods that are out now are gonna break a lot of saves after the first or second patch comes out....

With Fallout, I never play the game more then once.

Yes, I am aware there are players who like to play multiple runthroughs, but I am not one of them.

RPGs like Fallout are so complex, it's too much work to do everything for a second or third time.

So any mods I install will have to be compatible with my current savegames, as I am not redoing all the progress I have made (it's a lot!) from a blank state!

I think modding the map won't have any actual effect on the Settlement function, not if it is made properly.

All the code instructions will just identify the prewar map as Sanctuary Hills, not the old one.

And if it meshes neatly that way, then I can build my stuff around the modded version just like you would do with the postwar version.