i think, for the main room, instead of making the typical living room, you could build something for your town residents! i did this w my main room too- it's a minimalist, plant-y art classroom, bc my mayor has a side job teaching art to my town residents! you could do something like that, or similar public town spaces are: public library (lots of bookshelves, strapped books, couches, and classic desks), classroom (i suggest putting a more unique spin on it instead of your standard classroom- a magic school would be pretty cool! decorate with silver ores, lunar horizon, aurora screens, witch's robe and hat, and plenty of kiki & lala wands!), & of course, the typical cafe (you could make this one different by giving it a minimalist vibe- minimalist series, alpine panels, hanging plants, white brick wall, and maybe a stained glass- instead of the common, girly, french cafe style).
hope you find the room of your dreams!!!