New York style pizza is ideally had in New York City, which you won't be going through. That's not to say you can't get decent similar pies other places, but IMHO it's not quite authentic, kind of like getting Chicago-style pizza outside of the Chicago area.
Other food stuff:
Buffalo wings in Buffalo.
Duff's is one appropriate choice and where we usually went for Buffalo wings near Buffalo when I was a student at RIT.
If you have an iron stomach, a garbage plate from
Nick Tahou's is a Rochester regional dish. They're actually not bad tasting--just not very small, very healthy, or very refined cuisine.
Amusement parks--this list is probably not complete:
Seabreeze in Rochester is a neat smallish family-owned traditional park.
Darien Lake is a six flags park between Rochester and Buffalo.
Waldameer in Erie, PA
Cedar Point in Sandusky, OH, a quite large park with many roller coasters.
Museums and miscellaneous--very incomplete:
There are a number of exceptional NY state parks in the finger lakes region: Letchworth and Watkins Glen stand out.
There's the international boxing hall of fame if you're a boxing fanatic.
The George Eastman house in Rochester is worth visiting.
While it's out of the way of I-90, the Henry Ford near Detroit is very much worth the excursion to visit. Two days would not be too much time there.
Chicago has several excellent museums; the art institute is one of the few elite US art museums. There are several other exceptional museums in the city, too.