That looks like a really interesting route. However, for the way out of East London I'd recommend a more northerly route, via Chigwell Row, Stapleford Abbotts, Navestock, Doddinghurst, Wyatt's Green, Mountnessing (roughly)--a bit hillier, but worth it, unless you really aim to make time on the main road. The route from just south of Ingatestone is spot on, I think.
That looks like a really interesting route. However, for the way out of East London I'd recommend a more northerly route, via Chigwell Row, Stapleford Abbotts, Navestock, Doddinghurst, Wyatt's Green, Mountnessing (roughly)--a bit hillier, but worth it, unless you really aim to make time on the main road. The route from just south of Ingatestone is spot on, I think.