Even in Kent there are some 'white knuckle' rides. My favourite route has to be Stagecoach route 11, which runs between Canterbury and Westwood Cross (in Thanet) through various pretty villages, traditional Kentish vineyards and orchards, and past the former Kent International Airport at Manston. It is even allocated double-deckers (the only reason being it is inter-worked with busier route 9). It surprisingly has more passengers than you'd expect given the size of the villages.
From Canterbury, at Littlebourne the bus turns off the busy A257 by driving on to the other side of the road in order to make the turn into the lane down to the brilliantly named Wickhambreux and Ickham. These are the narrowest lanes of the route, and buses are often confronted by speeding vans and Land Rovers who only realise a huge double-decker bus is coming at the last minute. It goes through Wingham, then Preston, Stourmouth, Plucks Gutter, Minster, Manston and Westwood.
Thanks to the tight timetable, and buses often getting held up by the awful traffic of Thanet and Canterbury, drivers often have their foot down.
Possibly the best route in Kent if you want double-deckers down narrow country lanes (without having to go on a school bus!).