The Ultimate Way To Play The Sims 4 (Dual Monitors Multiplayer Mod)
The Sims 4 Multiplayer Mod works pretty flawlessly as if it were made for the game originally and can be a lot of fun to play with others.
If you want to still play on your own, however (and have two PC's or a PC and laptop laying around) download
https://www.sharemouse.com/ and you can have a monitor dedicated to each Sim (just move your mouse to the edge of one monitor and it'll appear on the other machine to control that one).
Example in action:
https://www.youtube.com/watch?v=HN3xWaHhLkU
Doing this drastically enhances the game. It's hard to show while holding up a phone, but you can have different Sims in completely different parts of the world or doing different things... or working together to create something.
It's hard to describe just how effective this mod changes the game, but the world somehow feels a lot bigger. In build-mode, you also get an extra camera/viewpoint to see what you're building. Amazing work to all the modders who made this mod possible!