I assume you'll be taking I90 between Niagara Falls and NYC. That's the route we took last summer and we stayed at Darien Lake Theme Park Resort just East of Buffalo. We left wishing we had stayed more than the one night we did. If you're travelling with kids you won't regret it. They have a full range of campsites available and you can walk from your site in & out of the theme park to your hearts content.
2007 Shamrock F19 hybrid - 2010 (22 nights), 2011 (24 nights), 2012 (11 nights)
2013 Surveyor Select 235RKS - 2012 (6 nights), 2013 (32 nights), 2014 (26 nights), 2015 (37 nights), 2016 (14 nights)