London Buses - Route 251 from Edgware to Arnos Grove 

Full route between Edgware, Station Road and Arnos Grove Station. Once you get past Mill Hill Broadway, this becomes one of the prettiest routes in North London, skirting delightful old Mill Hill and passing through the heart of rural Totteridge, where you will find some very pricey residential real estate (average £3.9 million on The Common).
The last time I rode this route, it was operated by a London Transport RF-type, with more steps (but more seats!). It was also home once to the Bristol LH, a low water mark in British bus development. The Enviros may not be the quietest buses but they nip along quite briskly.