Stagecoach East Kent route 89 Canterbury to Dover via Eythorne. Very rural ride but including former pit villages! Every hour and usually double-deck, taking about 1 1/4 hours (from centre of Dover, though bus starts at Docks). In fact it is hard to go wrong on East Kent buses. Just go to Canterbury bus station and take your pick from the frequent double-deck departures going here there and everywhere. Stagecoach website for timetables.

See http://www.stagecoachbus.com/eastkent/