Master Bedroom, Kids Room, The Way Out
So you get to the trailer, but your princess is in another castle.
Lucas has taken both Zoe & Mia, and arranged some games for you. Lovely. Kick off the festivities by looking in the fridge, where you find the deputy's head half- mutated into a Moldy.
There's a note on the back, cordially inviting you to the Dissection Room (this is the room where the deputy's body was hanging earlier, just before your power-tool duel with Jack). Make use of the inventory chest before heading out- you'll need some space, and you won't be doing much fighting. A pistol should keep you covered- shotgun if you must, but no extra rounds. Re-enter the house and make for the underlevels (In through the front door, left through a Scorpion door, left down a hall, and right down the stairs).
When you get to the boiler room, you'll find Grams waiting for you, though again she's a mute, unassaultable presence. Just past her is an ambush- after you go down the steps and turn right, the wall just behind the lightbulb will explode toward, carrying a new type of Moldy (spidery, like Marguerite, and with an annoying small head).
Sprint past it to the Dissection Room(hard right into the arena room, right to see the stairs, and then the door to your right immediately at the top of the stairs. Shut it behind you and you won't be followed).
No new loot in the root, save for what Lucas has hidden inside the deputy. Sigh. Follow instructions to snag the Snake Key.
You may remember this bit from the last time you were here- once you leave the dissection room, go right (crossing the platform where the last dogshead key was hung), down the stairs, and the Snake Door is immediately to the right- at the very foot of the stairs).
Follow that path, but follow it sprinting, because three Moldies will be chasing you. Luckily they're still dumb, and run into each other a lot, so you should have no trouble unlocking the door with time to spare. This passage leads to a secret door in the same room where you found the Scorpion Key. Make a beeline for the door back upstairs. There's an Arachno-Moldy lurking by the stair door that's surprisingly tenacious and ahrd to dodge. Go ahead and spend a few bullets to take him out of the equation.
Save at the top of the stairs, and make sure you have a prety clear inventory. We're going to be looting, not fighting. Go out into the main hall. Two Moldies are lurking here, a basic and a scythe-arm, but it takes them a few moments to spawn, and you'll probably be at the door leading to the Rec Room area before they're fully on their feet. Even if you're not, they're slow, and easy to dodge in all this space.
Run up the near stairs (or whichever stairs aren't Moldified), to the snake door here (Almost directly above the Scorpion Door on the first floor).
Close it behind you to discourage pursuit.
Oh, look- Grammy Grams is here waiting for you. That's.... nice. Ransack the room for ammo and components, of which there are many scattered about. When you're done, or you've run out of inventory space, search the Storage Room here as well. Front and center is a wire rack with a Backpack up top- use it to expand your inventory once again.
You can also find a note here detailing how to get the grenade launcher (which we already got), and a new Treasure Photo.
Take one last pass through the room for other loot, then return to the Master Bedroom and look at the Master Bed.
I don't want to jump to conclusions, but I think there might be a secret passage under there! Examine the globe on the bedstand for a note (which is a file entry for The Devil is in the Details), and then set the clock to the same time as every other clock in the house (10:15pm). The bed slides aside to reveal a narrow wooden passage, ending in a small mechano-abattoir.
I guess now we know where that drippy gate out front was made (wait, did the deputy see that gate? And he still didn't call for backup?). Anyway, there's some ammo to be had here, and the red access card on the table.
By now, the bed will have closed behind you (which seems like terrible design for a secret passage). The room you're in is actually the basement Workshop- that locked door you've passed so many times before.
Unlock the door, and sprint for the stairs, brushing past a Moldie or two. Pop into the safe room to throw off lingering pursuit, then it's back to the Main Hall. The two gooey doofs are still here, but evade them as before, this time making for the Rec Room area, which has grown moldier in our absence. Aim for the Snake door to your left, past the football helmet
Close the door behind you, and toss the room for a surprising amount of ammo, given it's a kid's room. Or unsurprising, when you consider the kid was Lucas.
Be sure to read his journal for the related file entries, and snag a lockpick from a vase on the shelf- the precise same sort of vase that was by the back door, and also held a lockpick (is there really just a special sort of vase for that?) Examine the trophy-lamp for a red button that will grant access to the attic.
Climb the ladder. Despite the journal entries, there is no transfigured Oliver up here- not even a skeleton. Open the cabinet immediately in front of you for VHS tape.
There's also an invoice on the floor saying that it took Trevor & Chamberlain Construction 20 days to install the Sky Hunter shadow puzzle. So now we know that.
Right next to the invoice are two wooden toys on shelves- a model shotgun and a toy axe. Grab them both. Solve the shadowpuzzle to reveal the second access card.
Take it and return the Main Hall - the gruesome twosome should have disappeared. Return to the shotgun niche and swap out the broken shotgun for the wooden model.
Passing by the phone will trigger a call from Lucas, but it's all old info. Return to the yard. There are now one or more ArachnoMoldies lurking in the underbrush here- you can dodge them or kill them (they're much easier to take out on open ground). Either way, make for the overgrown corner of the porch where we found the shadow puzzle earlier.
Use the toy axe on the plinth, and line it up to the barely visible components of a '7' on the board. This opens the nearby box for a second dose of stabiliser (beyond the one for sale in Zoe's trailer).
Speaking of which, now's a good a time as any to retreat to the trailer, save our game, and pop in the cassette we found in the Attic. You may want to play it through once on your own- it's an escape-the-room type puzzle, and it's not bad (though it is horrific). Once you've figured it all out, replay the tape with an eye for speed to get the 'Out Before Dessert' achievement, which involves solving the puzzle in under five minutes.
The steps there are-
Grab the candle from the automaton.
Hard left into the kitchen, then right into the cake room.
Stand in front of the cake to trigger Lucas's monologue, during which you should stand right in front of the keg.
The moment he's done talking, take the winding key.
Turn left and enter the box combo - doll in a noose, crow on a rock, baby (you discover this by using a telescope in the toilet, washed clean by the cake-room shower, on tv array past the kitchen, but we don't have that kind of time now). Grab the straw doll.
Walk to the stove and light the doll on fire, getting a dummy finger.
Light the candle.
Turn left and walk to the door past the tv screens. Ignite the cord to open the door
Near the far end of the room toward the right is a small yellow balloon mixed in with all the other balloons. You don't need be able to see it to get it, just be close enough to the object marker.
Go back toward the kitchen, but veering right before you reach to stove area. Attach the balloon to the gaspipe here. You'll wind up with a quill pen.
Return to the automaton. Use the dummy finger on its hand, then use the quill on its hand, then use the Windup Key on its torso.
Take you new code back to the balloon room, and enter it in the combo lock at the far end of the room, to the left.
Grab the valve wheel, and take it back to the cake room, using it on the pipe just inside the door, to the left.
Light the candle on the stove, and place it on the cake.
This doesn't end well for Clancy, alas, but you get an achievement out of it, and Ethan gains a bit of insight into a future challenge.
You now have both keycards, and are close to leaving the mansion area of the game forever. Now's a good time to pick up anything you kept meaning to get back to, and as well as checking your collectibles. By this point in the game, if you're getting everything, you should have- 12 Mr Everybody Figures 12 Pelican Coins 21 Files You can check the first two by looking under the 'Stats' option from the Pause Screen, and the last by checking your journal from the map/objectives screen (reachable through the 'V' key). They aren't checked, but you should also have two backpacks, three treasure photos, and one dose each of steroids and stabilizer, not counting the ones in Zoe's trailer. If you're short on supplies, you may particularly want to sweep through the Old House one last time- with Marguerite dead the hives are all gone, and you can claim their guarded items with impunity. You can also check the mansion- all the Main Hall areas are now enemy free, and there's a lone ScytheMold in the kitchen area, easily evaded. The basement, alas, is crawling with Moldies of all types, and the lights are out. Also, Grams is hanging out in the crawl space under the laundry room. So that's... good.
When you're all caught up, arm yourself for a fight (with an extra helping of pistol ammo), and use the keycards to unlock the gate to Lucas' little wonderland.