Also, downstream in the Lea Bridge Road area, much of this is on my daily commute, and Waltham Forest Council have blown several decade's budget on quality cycle facilities.
On the Lea Bridge Road cycle path, once you've passed the ice rink, and before you get to the cyclist/pedestrian bridge, just beyond the digital-laser (I kid you not) cyclist counter display, turn left and cross Walthamstow Marshes using the tarmac'd path (Unless you are riding in a group, don't do this after dark - it is unlit, and is known for attracting aggro).On the plus side, this is the part of my commute where I get to see horses, cows and all manner of water-fowl - which isn't bad when you consider that all of my commute is within London postcodes.
At the end of the path, go through the car-park and turn right onto the traffic-free Coppermill Lane.
Take your first left onto Edward Road.
At the end of Edward Road turn left, and turn right at the lights by Blackhorse Lane Tube Station.
From the point where I started to describe this route, this is the first time you'll encounter anything like traffic.
Follow this, the A503/ Forest Road all the way to the end, where you'll re-join the traditional Dun-Run route at the big roundabout which crosses the North Circ - the one with a cattle grid as you exit it.