Keep in mind there is a 20 room limit. So, if you're gonna plan on getting a dungeon with treasure room, serious decisions must be made. There is 20 possible rooms on the list, with a 20 room limit, and you need 2 bedrooms to have a servant, so you can't even have all of them. Make sure you plan ahead, especially on the rooms that have money invested in, as you don't want to have to rebuild those. Visit a friends house with higher construction, and ask him about all the mistakes he made. He'll have some advice for you.