Kent is not one audience. A campaign is planned around an individual town or local catchment and a date, rather than trying to reach the whole county in one drop. These are the principal places a Kent flyer or leaflet brief can centre on.
In mid and west Kent, that might be an event audience in Maidstone, a show night in Tunbridge Wells, or a town-centre launch in Tonbridge or Sevenoaks. In north Kent, it could be Dartford or Gravesend ahead of a local date, or Medway, with Rochester at its historic centre.
In east Kent and on the coast, a brief might centre on Canterbury, Ashford or Folkestone, or on Margate and the wider Thanet catchment when a seaside venue or event needs people to turn up.
Naming a town does not mean every street in it. The exact places, times and sessions are agreed on the brief, around where the audience will actually be.