It looks like a lot of campgrounds, Audubon nature reserves, state parks, and the only major city is Providence which is museums and food.
If you only have one day, and it’s open, I would recommend visiting Rhode Island School of Design’s museum and campus. The RISD museum was surprisingly nice. Small but uncrowded - it was the type of place I could bring a sketch pad and draw for hours. There are probably other museums and attractions nearby, along with nice places to eat and drink. I don’t know much about outside of Providence though.
It’s an art museum?
Rhode Island School of Design is one of the top art schools in the US. They have an art museum on campus that houses pieces like you’d find at actual city museums plus works by their students. https://www.risd.edu/
