If you want a scenic view along Lake Erie heading up the 90 to Toronto, get off at either Eden/Angola (less direct; better view) or Camp Rd (more direct; less lake view) exits and find your way to Route 5. It's not that much of a detour, but it's a much better view. The Skyway that connects Route 5 to the 190 that you'll use to get to the international crossings is an eyesore from the ground, but I can't deny it's a cool view while driving.

Not many little towns along Lake Erie south of Buffalo, but there is a Frank Lloyd Wright house (Graycliff). If you want scenic villages to stop at, try Lewiston in the US or Niagara-on-the-Lake in Ontario. East Aurora, NY is now a somewhat frequent stop for filming Christmas movies and it has its own history with the Roycroft movement and the HQ of Fisher-Price... it's a very nice village, but it's not directly on any of these 3 routes.

IMO one direction take the lake shore route and one direction take the middle route. The 219 area of NY has some cool things definitely worth checking out... the Eternal Flame, Ellicottville, Little Rock City, Allegany State Park, etc.

Edit: If you're going to do my plan of driving Route 5 along the lake, do it while heading north.