bro im thinking the same thing there MUST be multiple rooms there were so many rooms on the other floors when they went around to rescue people

His territory only increases a certain amount with every level up and the first time it increased they gave him his neighbors house, the next time it presumably gave him the Halls but it is yet to give him more rooms at least not on screen.

Because the MC is an idiot who can't play Kingdom Simulator or Sims, he should be managing things behind the scenes, so he wants to get up close and personal. That's why everyone is cramped up in one space...

Probably something like 1B or 1T, which needs to be a separate purchase from running a city.

Vassals can leave the building which means vassals can bring back bigger prizes. I see no reason why the Adventure's Guild's payment system couldn't be done with brought in monsters, after some from the top was taken to maintain the city. A mother's love could harvest all types of monsters. Especially one conscious of her actions like that. Her current skill is also separate from her Vassal skill.