You get this achievement by reaching Maximum Happiness in a Large Settlement
How to get
Reach Maximum Happiness in a Large Settlement
NOTE: Credit for most of the tips here taken from a reddit post by "/u/never-enough-hops" at the /r/fo4 subreddit
- Do not use sanctuary - It's stated in one of the above guides but it bears repeating. Sanctuary has some special NPCs in it, at least one of which can decide he just doesn't want to obey orders
- Every settlement can be "large" - It's about the "Size" bar at the top, not the physical area of the settlement.
- Do not use a "railroad" settlement - This one screwed me up on my first attempt. I tried to use the Murkwater Construction Site and a railroad operative showed up. I couldn't assign him and I'm pretty sure he counted toward my happiness, because I got stuck at 96. This may not be the reason I got stuck but there are other options so don't risk it
- Do not have any outgoing Supply Lines from your chosen location - Provisioners (the people running the supply line) count toward your population, but you obviously can't reassign them to a clinic, so that's a dead spot in your population.
- Pick a location that has enough prebuilt housing - You want to put beds in a prebuilt house for two reasons: 1) People have reported bugs with settlements not registering your settlements as "right" when you're away from the location and the bedding is in a player constructed houses and 2) You're going to need all of the extra settlement size because...
- Only build structures necessary for the achievement - Clinics, water pumps, mutfruit, beds, heavy turrets and pictures. Those are the only things you should be building. After you have the basic requirements every guide tells you to do spend the rest of the settlement's allocated size on hanging pictures of cats and beagles on every flat surface. Max out your settlement size with pictures. The more pictures the better your happiness will go
- Destroy everything in the settlement that was there before you showed up - This frees up more size for pictures
- You do NOT have to hang around the settlement until you're already in the mid 90s for happiness - A lot of the guides state after you've got the prerequisite stuff figured out you need to do a "Wait 5 minutes in real life time in build mode, wait 24 hours in a bed, repeat" method for letting the happiness work its way up. You'll want to do that, for sure, but there's no need until the settlement is already in the 90s. My first failed attempt got to 96 all by itself and my winning one was at 94 when I decided to head over. So get things set up and go do other stuff in the game, occasionally checking on your chosen settlement.
- Wait for 48 hours, not 24 - When I hit 96 happiness I noticed it wasn't continuing to go up consistently every 24 hours... but every 48 seemed to do the trick.
- Distinguish your farmers - This settlement tip gets mentioned pretty much every time, but you can change your settlers equipment... and since you'll only have 4 farmers put them in some distinctive clothing. Mine were all naked except for a sailor hat and camo bandanna.