Not sure if it's helpful, but when we did the Lavenham ride a few years ago, we took a rather lovely route out of Brentwood (where we met), courtesy of Stu_F, that I remember fondly:
I suppose if you can get yourself up to Brentwood from the Dartford crossing, which seems quite straightforward, that might be a good way of bypassing London to the east.
From Ongar, it's easy to get to Stortford or bypass it, although in the latter case I think I'd go via Dunmow, as it's a total pain to get past Stansted on its eastern side. It may look like a detour, but it's much easier.
Not sure if it's helpful, but when we did the Lavenham ride a few years ago, we took a rather lovely route out of Brentwood (where we met), courtesy of Stu_F, that I remember fondly:
https://www.lfgss.com/conversations/214251/
It's the bit between Brentwood and Ongar here:
http://ridewithgps.com/routes/1607370
I suppose if you can get yourself up to Brentwood from the Dartford crossing, which seems quite straightforward, that might be a good way of bypassing London to the east.
From Ongar, it's easy to get to Stortford or bypass it, although in the latter case I think I'd go via Dunmow, as it's a total pain to get past Stansted on its eastern side. It may look like a detour, but it's much easier.