this dialect has mostly been replaced in the past century and a half by RP and cockney-derived "estuary dialect". i hope there are still people who speak it somewhere.
a dictionary of the kentish dialect has quotations and (non ipa) phonetic transcriptions where they're useful. the transcriptions and spellings are made with a nonrhotic accent in mind, even though the dialect was traditionally rhotic.
alphabet of kenticisms and collection of proverbial sayings used in kent was originally written in 1736, so it describes an even less levelled dialect than most dialect resources. the glossic transcriptions added by skeat, the editor, seem inaccurate.
the paper the dialect of kent in the fourteenth century goes over features of medieval kentish, as well as comparing it to the modern traditional dialect.
@kenticisms on twitter is an account dedicated to posting about this dialect.