I've went back and forth on the more crazy stuff. But, it would be fun. Lol.
I would like to maybe do some of the stuff like you mentioned with the UFO. Make some small little POIs that will give you a quest when you get near them to investigate them or something.
I feel like maybe I should just combine the Wasteland Weapons and Nuka Colas mod. I've already got several custom blocks in the Nuka Colas mod that would be good in some of the POIs I wanna make.
Well, I forgot to tell you that today I finally learned how to insert a POI into the world using world editor after several failed attempts, so I finally had a chance to actually try your Nuka Factory POI. I intentionally placed it fairly close to the spawn point, so that I could visit the factory as soon as I spawn in the world on day 1. Man that was some dejavu right there, I have to tell you! It was pretty fun to play it and playing on the longest day settings, it was already day 3 when I finished the quest to visit the trader, so you can see I had a lot of fun in the factory lol.
But for some reason the factory did not contain your Nuka cola vending machine. I guess it's because you created it later and didn't update the POI? If you updated the factory with these machines, that would be really cool. I also had a strange idea about the terminals too. If they were actually blocks, you could probably make them useable in similar way Snufkin made his slot machines, they would simply show you the screen of the terminal (loaded picture) with some texts on it. Probably not much use in it, but you know, maybe it would enhance the story telling there. Also, do you know if anyone ever made an actual Fallout Vault? I saw some thread about it, but I couldn't find any public release of the project.

I'm playing with Creature Pack which already contains Vault dwellers, overseers, power armor guys etc., so it would be pretty fun if they spawned inside the vault!
Speaking of Fallout mods in general, maybe you could team up with Vanblam who has been making some interesting Fallout items for 7 Days to Die too and see where that goes. He has not released anything to public, but what he showed is pretty cool. Check it out
here, if you haven't. Man, if you guys created some bigger Fallout project that would include some of the best things from Fallout universe, me and my niece would love to play with it, that's already two people interested. I made a screenshot from the office in your Nuka Cola Factory and I will show it to her, she will love it as much as I did, I'm sure.
Later it turned out my mod load order was kinda broken (again, sigh), so I have to figure out how to fix it, but still. I loved the experience and I will play through it again as soon as I check the whole chain of mods one piece by one until I find the problem lol