313 Chingford to Potters Bar. Out into Hertfordshire through a village with the unlikely name of Botany Bay. Every 20 mins most of the time.

Time table can be found here
http://www.londonbusroutes.net/times/313.htm

Return to London via:

298 Potters Bar to Arnos Grove via Cockfosters. Again, mostly every 20 mins. At Potters Bar you will find proper timetables on the stops. They are produced (doubtless reluctantly) by TfL because Hertfordshire (who are responsible for the stops here) want things done properly!

Timetable here

http://www.londonbusroutes.net/times/298.htm