I like the empty world Redwood Harbor by My Sim Realty. Sometimes I just want to play instead of building for weeks at a time, so I appreciate premade empty worlds. You can also make your own empty world if you’re familiar with CAW. My Sim Realty has several very high quality empty worlds you can choose from.
My favorite is Deery Meadows if you want to build everything yourself or Redwood Harbor if you want all the rabbit holes and houses already built. The first step is installing an empty world. You could also use this guide if you play with story progression, but want a custom world filled with your own Sims.
In this guide, I use a premade empty world and populate it with Sims for rotational gameplay. This is NOT a tutorial on using Create-a-World (CAW). This is how I setup a custom world in The Sims 3, starting from scratch and building up my world from nothing (similar to my Sims 2 method).
