TravelPod has a posting about someone’s recent trip to Niagara Falls:
Today we got up early to take Chris to Niagara Falls since he has never been there.
We had a leisurely breakfast and then parked at the Casino (it’s really cheap there, especially if you are a casino member, it’s free to join, and then you usually get free parking)
By the way, another place for free parking is in the Comfort Inn at the top of Clifton Hill. Just park there, and tell the parking attendant you are going to Rumours nightclub/restaurant, then you’re good for the whole day.