chris, can't help you there, sorry, it ain't far from me but not my way, I go west through Tottenham etc
from what I recall of driving down the A13 that's a bear of a big road and a bit bloody fast, they has to be a good road apart from that I'd have thought?
ak, go clipless asap, they're brill after an initial period of getting used to them
do consider which type though and what sort of shoes more importantly, spds are fine but you can get shoes that let you walk around, I went for roadie ones and hobbling around isn't much fun and it's not good for the floor
getting a decent new bike soon and moves afoot to sign up with Lea Valley Cycle Club, they ride from Walthamstow town hall a few miles away, no idea where I'll fine the time from though
as for the Dunwich route, I'd cycle from Highams Park to London Fields to start and them almost exaclty retrace my route back to Epping Forest, ho hum