I used play the game without mods until about 2016 when I had finally figured out how to put them in as I had really wanted to have NRaas Traveler mod so that I could send my Sims to other worlds other than the world's from the World Adventure EP. Without that mod, it's impossible to visit the world's that came with the other EP' and the store worlds. The world's that you can travel to besides the WA worlds is the University of you have University and you're sending a sim to attend or to the future if you have the Into the Future EP. That's one of the things I like about TS4 is that you can travel between worlds or neighborhoods without the use of mods.