There is Branches of Niagara and a KOA on Grand Island which is about a 10-15 minute thruway/expressway ride to the Falls. There is also a KOA in Lewiston and the Four Mile Creek State Park nearby in Youngstown, those are 20-30 minutes away from the Falls. If you make it here I suggest you try Duffs for wings, they are better than the Anchor bar, also the french fries with gravy are fantastic. Being a WNY native we take for granted one of the beautiful things in we have in our own backyard, I'm thrilled to see all who have traveled here.
Safe travels, Chris