Apologies. I originally wrote Cleveland above (now corrected) but I meant Columbus. Two months ago I did also check Cleveland but preferred Columbus since it's closer to Buffalo.
Fairly easy drive on the I90 to Buffalo from Columbus. Peace Bridge crossing is the closest to this route but you can easily access any of the 4 bridges if you are on the I90.
Another data point: I found a car for my friends (who have no car rental status) this morning from Columbus-YYZ for just over $200 US for a 24 hr rental. Hope this is helpful to others.