Our tortoise can go anywhere in the house it wants as it's proofed to do so, however, it doesnt and it chooses to stay in the room it's in. We don't have it set up jsut for the tortoise but it's tortoise proofed and has a large area in there of its own. Eventually when the tuff shed is insulated it will likely be made into its specific room.In your first post, you said the tortoise has free range of the house. Then you said it likes to go under your bed. Is the dedicated bedroom for the tortoise your bedroom or does it have its own?
There is a thread on here somewhere in which someone dedicated a room of their house to their tortoise. They lined the floor with something waterproof, then filled it with substrate.
There are other people in cold climates who keep their large tortoises outdoors. They usually provide a heated barn for the tortoise and allow the tortoise out during the day, even in the snow.