No need to overnight in Hamilton. Leave early in the morning from Toronto, arrive 1.5 hours later in Niagara Falls. Walk around and look at the falls in the morning before it's too busy. Get back in your car at lunch and travel towards Niagara-on-the-Lake and take in a few wineries (just be careful how much you sample). Pick up a bottle or two (or pick up lots and have it shipped). Have supper in Niagara-on-the-Lake, then head back to the Falls to see them illuminated in the evening. Get back in car, 1.5 hours back to Toronto.

It's a long day, but it will be awesome for your first time in the Niagara area.

Again - don't stay in Hamilton.