Need Room for Rotational Play in Sunset Valley

I realize that not many people play the Sims 3 rotationally. At least, not many people document that type of gameplay online the way they do for the Sims 2, but I'm planning quite a big undertaking in my own personal game. I have added several families (including plans for new businesses / community lots) to Sunset Valley and plan to play them all in rotation Sims 2 style using NRAAS and other mods. However, I need room for the extra families and the expansion of descendants over time, and unfortunately there's no option to add more space via subhoods like there is in Sims 2. All that to say, does anyone have ideas / techniques (probably using create a world to modify the map I guess?) to expand Sunset Valley with more residential lots in a way that feels organic and keeps most of the premade houses intact?

P.S. ~ I know it might sound like if I like Sims 2 style rotational play then I would be better off playing that game, but I love so many things about the Sims 3 like the traits, customization, and open world detail, so I feel like I could better tell my sims' stories the way I want in that game, even if it takes some tweaking to get it working the way I need it to.