Note the 1841 census returns for Ashford (part), Bishopsbourne, Herne Bay, Reculver, Seasalter, Smarden, Sturry, Swalecliffe, Westbere and Whitstable do not survive.
Note the 1901 census returns for Deal do not survive
Some Kent libraries have card indexes to various census covering their immediate areas. See the Kent Libraries with local/family history resources link for library locations http://www.rootschat.com/forum/index.php/topic,6614.0.html