We'll second the motion on the Cooperstown Diner. Also, if you (and/or Mrs KingFisk) are up for something non-baseball-related,
the Fenimore Art Museum [
http://www.fenimoreartmuseum.org/ ] on Rte 80, overlooking Otsego Lake, is definitely worth a visit.
We recommend lunch on the veranda and a stroll down to the lake.
Not too much further off, the Iroquois Indian Museum [
http://iroquoismuseum.org/ ] and Howe Caverns [
http://howecaverns.com/ ]
are also well worth your time.