A mixture between one of the lootopias, one of the drifters, the storage mechanism of the hub game and the tiles setup of skygarden (so basically a big mixture of reused ideas)
The world is an "infinite" 2D grid. There are exactly two POIs:
House -- a procedural house full of furniture, which might be locked and might not, containing various items. Doors might also be locked on a different system.
Town -- a collection of shops that buy various things for their exact value. Also always a Carter store.
Houses are way more common (maybe a 7:1 ratio), but tiles can be blank. Directions use the NSEW thing instead of positive and negative coordinates. NS first.
The main gimmick of the game is the storage system, lifted from one of the hub systems. Basically you can store things in a Carryall, and these can matryoshka recursively. One of them is permanently bolted to your Cart. Others have to be bought at a Carter.
You have a limited personal inventory, and you have to leave your Cart outside a house (but can freely bring it inside a shop). Your personal inventory can also be upgraded at a Carter but you get decelerating returns here (+10 gold each slot, starting at 10 gold).
Houses are a 3D grid with F=1-3 floors, and X=3-5 and Y=3-5. There's exactly one entrance into another floor, but your starting floor(S) varies -- so if you start on floor 1 there will be both stairs going down and a ladder going up, but floor 0 would have a ladder down at the starting floor and a ladder at the next one. If you're on floor 2 then same deal but with staircases.
Entrances are variable as well (somewhere along the bottom), but ladders and stairs never appear on the starting room.
Doors
There's a D chance that a direction will have a door, and if it does, a L chance it'll be locked.
D can be 20-80 and L can also be 20-80.
Furniture
Each room has 0-3 pieces of furniture, randomized in a pyramid way.
Furniture can be locked with FL=20-80% chance.
Furniture picks a few types from some giant procedural list that arranges categories, weights of them and amt ranges. There's a color, a material and a furniture type so three degrees of freedom. A special fixture on your Cart can look up the lists here (which is important).
Variables
All the variables here are set by the house itself (this will be important later).