I've driven that route many many times to Niagara Falls and beyond. It's a dull trip with rare traffic problems (maybe heading out of PIT, and some minor backups in Erie). As CBF said, if weather is not a factor then it's no sweat. I budget four hours to get to Niagara Falls. I always smirk that once you get into New York you immediately hit your first toll "Welcome to New York, now pay up!"