The other day, I was thinking to myself about any dream goals I could add to my list, and building a house came into mind. A mansion, that I could revisit in each dream, and have it be exactly the same each time, and having the surrounding area the same. Is it possible to do this? If it is, it would be great because I can probably construct cities or entire worlds 
I think it’s definitely possible to do so, you just have to believe you can. However, it will probably depend on your experience with LD’ing, your amount of control, and how vivid and detailed your dreams are. There are plenty of others that I have read about who can do this as well. The only thing is that it is likely to have slight changes all of the time because of the nature of dreams, but major parts like walls probably would always stay the same. I can create a safe space in my meditations that always looks the same, so I don’t see why you can’t do it in a dream. Also, I have had quite a few dreams that take place in the same dream landscape and it looks pretty similar. I would try to sketch out your mansion IRL. There are a few dream incubation techniques that you could use with your sketch that might help you out a lot, especially with the consistency of the building.
As long as you believe you can, you can. Good Luck!!! 
Hello! Your dreaming mind has access to vital information that is not readily available to you when you are awake. Your dreams serve as a window to your subconscious and reveal your secret desires and feelings…
That’sssssss a nissse houssssse you got there, it’d be a sssshame if sssomething were to happen to it!
In LD’s the house should be chasing the creeper.
You can find more about this topic in “Exploring the world of lucid dream” (btw. Great book, my own opinion). Just red that chapter, and i think it’s great idea also my new goal.
But here is short version. You can create your own “dream workshop”(or mansion, base of lucid operation). Returning there every single night should be easier if you put yourself in the details. Posters of your favorite band, tools needed for your hobby or profession. Put some stuff realted to your interests (full discography of U2, or pond if you like fishing). You can hire your friends or role models (albert einstain) as assistants or simply ask them to live with you.
For some examples you can read Writer’sCube DJ. If I understand right he created “The Citadel” wich is really big dream workshop with installed some sort of transportaion device to help him move around dream world, and return to his favorite dreamscapes.
[community.ld4all.com/t/writerscubes-dreamworld-log-dream-diary-3/29215/1)
Ha, I actually do have that book, I just never finished it. Can you tell me what page that topic is on? I’ll try and find it myself too. Thanks!
It’s chapter 9: Creative Problem Solving. For me it is page 100, but there may be different edition.