Traveling from Canada to the US through Niagara Falls or Buffalo is very easy for Canadians. You don't need a passport just a photo id you only need the passport if you are traveling by air. If you "look" Canadian they don't even take the paperwork from you, that does concern me a bit. The last five times I have crossed the border and I am born in Canada, no-one even took my paperwork.
"where you born?" "where you going?" "Citizenship?" and that's it , go ahead.

Daniel.............Toronto, CANADA