This. SO THIS.
Would love an 'Architect' NPC you could hire after you've built up your first settlement, and tell him to "Copy this design" Allows me to assign a name to it "Sanctuary 1" etc, and he.. ooh, brainstorm. He has a virtual reality pod you sit in, and it just brings you into a construction area of your choice (can choose from any of the settlements you can acquire) so it loads the proper zone, complete with all the junk.
So you can run around in there, scrap what you need to for things to fit, then build up the town how you like, save the plans, and now you have a 'Set of Plans: Oberland Station" etc so now when you get to the location in question, all you have to do is run around and grab what loot you want, then hire the Architect (for a fee +materials required for the buildout must be in the workshop of the town in question) tell him to get started, and depending on size/resources used, there's a build time, X many in game days till completion kind of thing. Then you can come back, voila there's your town.
Also... allow us to export these Sets of Plans to others, they can preview your build, and if they like it, download a copy of the plans, import them, and they're part of the Architect's Inventory when you trade with him.
Key Points:
You have to have an established baseline ie All junk that is scrappable must be scrapped first before the architect can do the build, but I fear too many people would miss a bush, or a picket fence post buried inside other clutter, and that just wouldn't work. Hence the VR pod idea, so you zone in on a virgin, unchanged settlement location, and since THIS information is the same, the Architect just needs to know which clutter to scrap to make the build work, because it recorded you destroying said scrap, this way, no person should have a problem installing a new town build, since he knows what needs to be scrapped so there's no clipping/illegal placement issues.
There should be an extra step/requirement. You're paying someone to do the work for you, either a 10% markup in mats requirements, or a scaling fee based on mats used etc. But you have to have some trade off, click a page insta max build Sanctuary/Castle with one button click. sorry, that's just too cheaty for me lol. I like the slow build up idea. Like a really big settlement takes a week to FULLY improve,
Tangental thought now: Since it's gonna take a week to fully improve the town, in those cases you could tell the Architect where to prioritize. "Build the walls first Jack, then get the crops in, after that you can start working on everything else, but Walls first.
Then as you swing through over the course of the week, after day 1 half the wall is built (if it's a big wall etc, obviously if you're just using 20 wall units to plug gaps in pre-existing structure then it shouldn't take as long) day 2 the wall is built but the gate/towers aren't installed yet. Day 3 the defenses and resources start getting put in, day 4 generators are installed, wiring being run... Day 5, ribbon cutting ceremony (siren blast announcement? bell ring for town gathering? anyway) your town is now complete, and all you had to do was do what you do best.
Kill crap, loot, repeat.