Well.
This sucks.
He goes back into the mine and shovels gravel until he gets a piece of flint--he has a furnace going, now, with a few iron ore in it and a few pieces of coal--takes an iron ingot, combines it with the flint to make a flint and steel, and heads back up to the surface.
He's not building a house here. He's going back to L'Manberg. He can make a campsite, maybe, or an outpost, or a tower, but he's not making a home.
He sets the stack of cobble on fire and walks around, talking and praying as he does. He feels less lonely, talking to people, even if they're incorporeal and can't talk back very well. (He's pretty sure there's more of them than usual, which he tries not to think about, in the same way he's trying not to think about how Tubbo prayed for guidance before going through with exile.) He's acutely aware that Paramin could come back at any time, that he has a limited amount of time to get logs and iron and food and everything before she comes back. He really does need food, though, so that's his first goal.
There's a ruined portal nearby with some glistering melons, and just beyond that, a village; he doesn't bother farming, just grabs some hay to turn into bread later before heading back. It's almost dark by the time he reaches the dirt-shack-with-a-door; he goes back to punching trees until night falls.