Well, hello to all terrarians out there! Today I present to you my incredible formula for building up your spawn for your future NPC accomodations, where you will keep all of your pesky merchants and have space for both any crafting stations you can wish for AND a gigantic storage for all of one's necessities. Without further ado, let's start!

What we shall begin from is the fact that this base will be under the ground, because we can definetly find something better to build on it.

First we gotta clear some space. You don't need a lot, about 50 blocks will be just enough. Though if you wish to build an arena above your base, you have to take care about a bigger field, because you'll need space to dodge. If you're a fancypants you can also mow a lawn when it grows back, so that nothing grows on it.

Vanilla Terraria has only 25 NPCs to offer, so that's how much rooms we need. Luckily for us, the number 25 is not only not prime, but it is also a square of 5, which means we can build a 5 by 5 grid of rooms. Let's start with digging a tunnel 27 blocks deep and 3 blocks wide. From block 2 and each 5 blocks place a platform. Then put a rope in the middle. Make some space for the first doors. After you're done with the base the tunnel can serve as a hellevator.

Now we dig out the space for the rooms themselves. Minimal living space for an NPC is 32 blocks of free space, so we dig out the 8 by 4 rectangles. Use Ruler tool to check if the sizes are correct.

Replace the walls with wood. This step is kinda optional, but I'm pretty sure you'd prefer a bunker to a literal ant mound.

Now we have to fill in the empty spaces with the walls. You can't just leave the naturally generated walls, because the NPCs do not see them. So you gotta get some lumber for it. Where there's a door to be placed, the walls are unnecessary.

Add the furniture. For an NPC the suitable housing consists of 32 blocks of free space, a "table", a seating and a source of light. In the description I mentioned that we're making a base both for us and the NPCs, and for this we have the miraculous invention called "dressers", which don't just count as a table, but also have chests in them! 25 of those will be just enough to have pretty much all of the items you might ever need to have. Don't forget to add some building stations later (workbench, furnace, etc.)

The Truffle NPC requires a musroom biome to move in. Which means we need one. You can do it in any period, hardmode or not, but I suggest doing it when he's available so that the rest of time you could spend collecting bunnies, butterflies and other critters, since mushroom biome prevents them from spawning. The biome is set to mushroom when there are 100 blocks of it loaded simultaneously. However if I'm not wrong, Truffle will only move in the underground mushroom housing, but will return after his death or move to any mushroom biome house. Just in case, try building an extra room in the underground and then break it. You can also remove one of the seeds when he moves in because of the way housing works: if conditions for an NPC to live in his room are no longer met, but there are no suitable housings anywhere in the world, they will keep living in their assigned house.

Counting all of the steps above up to be completed, you will need the following:

Foreground walls: 55x4+46=266 wood
Dressers: 25x16=400 wood
Doors: 25x6=150 wood
Chairs: 25x4=100 wood
Background walls: 25x32:4=25x8=200 wood
Light: 25 torches
Mushroom biome: 100 mud and mushrooms grass seeds

TOTAL: 1116 wood, 25 torches, 100 mud, 100 mushroom grass seeds.

I really love adding this acutator door to my base, beacuse it allows to easily fight against any event.
The lever on the left opens the trapdoor, and the lever on the right unlocks the small shooting peephole. This simple strat counter most of the enemies in the events.

Killing chamber
If you left some space above your base, you can clear the jungle temple from traps after you defeated The Golem and bring them back. Yellow pressure pads are activated by everything except the players (YOUR PETS WILL TRIGGER IT AS WELL!). Using The Almighty, Spectacular and Untamable Lord Hoik (also known as "Magic Sticks"), the enemies will enter the chamber there is no way out of.

That sums up my guide. After finishing this contraption, everything a terrarian may ever need will be right beside you on the spawn. Good luck with your adventures!

If you don't speak english, russian version is available here:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3511040682