Don't plan to eat in Niagara Falls. It's way too expensive there and parking can be a mess. Get there early if you plan to stop and sight see. Plan to spend $20 or more for parking if you aren't lucky enough to find something along the road.
If you go the back way to Niagara on the Lake (along the river instead of taking the highway) there are some beautiful views and some nice restaurants there. If the Pharmacy Museum is open, have a quick look inside. It's worthwhile. Some nice shops to wander through.
Watson