Where are you staying?
Near Cooperstown I recommend Council Rock Brewery for food and beer. Cooperstown Brewing, Red Shed Brewing, & Brewery Ommegang for beer. All south of the village and require a drive. You can do it in a simple loop.
In Cooperstown village itself the Main Street strip and the HOF itself are must sees. I’d also recommend walking down to Otsego Lake (aka Lake Glimmerglass from the James Fenimore Cooper sagas), the source of the Susquehanna River. I also like the New York State Historical Society’s “Farmers Museum.”
If you are staying in Oneonta, “Brooks BBQ” is famous for their chicken. Just south of Oneonta is the NW edge of the Catskills and some surprising gems. “Breakfast Club” in the tiny village of Jefferson for breakfast, “Tulip and Rose” in Franklin for dinner (menu changes weekly, check online on Tuesdays for new menu), “Sal’s Meat Center” in Bloomville for subs, “Table on Ten” also in Bloomville for oven fired pizza (way limited hours & reservations required ), “Mama Maria’s” north of Stamford for “east coast” pizza.