I have spas in Oasis Springs, Sulani, Evergreen Harbor, Mt. Komorebi, Tartosa and Granite Falls in my game. I don't know that I feel any world has a "hippie vibe" but I like to have options when it comes to a wellness retreat. The spas I have in Granite Falls and Sulani also have what are essentially "hotel suites" in the upper floor, so that my sims can live at them for a few days if I want them to.
You don't need a lot to assigned residential to have your sims spend an extended time there, you just need it to have facilities to meet all of their needs, including sleep, and a mail box. Sure, they need a 'home lot' but you can easily have them never need to go to it.