On a basic level you can do this without using mods,which might be hard to believe but you can, thou using mods would help increase illusion that your actual playing in a different world. How this started was that I was trying to add the The Sims 4: Tropical Getaway Modpack has a standalone world, rather than a replacement world, in the end I ended up with two Granite falls.
I'm currently still at the early stages of testing. Hi it's my first post here, I've been trying to add new worlds to the sims games, I did have some success with this, I did think that they might be some desire to have the ability to double, treble the number of lots in your world.
